All right. I'm going to present evidence for Lucas's case in argumentative format for the sake of ease, so if I start to sound pissy, I encourage you not to take offense to it (
Xandercosm
).
The thing about Lucas is that he's very much overshadowed by Ness. Many pretend he's just a less-capable Ness (which, to an extent, is true), when he has all of the tools at his disposal. I'm going to run through all of them for you. Note that some of what I'll note was already covered by
@Feelicks, but I'll reference it here just for the sake of keeping things together.
Let's start with his standard attacks. His jab is very, very quick--tied for fastest in the game, coming out on Frame 2. It even hits behind Lucas, which is an incredible boxing option. His forward tilt is similar, only its damage output and spacing ability is better (when sweetspot), though it first activates on frame 7. Its sourspot can lock opponents who miss their tech or fall victim to one of his infamous footstool combos. His down tilt is also tied for quickest in the game, coming out on frame 3. It can combo into itself, a forward tilt, an up tilt, a grab, or (in some cases) an aerial. It can also lock opponents if they're hit with its tip, which is helpful when you land too far away from your opponent during a 0-death. His sourspotted dash attack can combo into an up tilt at low percents and an up air at mid-percents, and its sweetspot sends opponents at a safe distance while inflicting a nice 11 damage. It works as a wonderful kill option despite its slow startup, as it has low endlag.
His specials are a slightly different story, but still a good one at that. His ability to wavebounce using special stick-PK Fire allows him to zone out opponents to the point of frustration. Even without B-stick, Lucas is still granted the gift of great mobility with this projectile's recoil if he chooses to retreat using it (though, electing not to use B-stick does put him at a disadvantage). PK Freeze is a situational ledgeguard--a good one, at that. It has a relatively small amount of ending lag for its size and mobility. This plays contrast to PK Thunder, which is a very bad option for ledgeguarding and attacking in general due to its moderately high amounts of endlag. PSI Magnet is a great tool for stalling offstage, producing an emergency hitbox, and, well, healing Lucas. Sometimes it can work as an approach option, and it works rather well should the opponent be caught off-guard. All of this combined with his ability to reverse his direction with it mid-air only means it's his best tool when offstage.
Lucas's aerials are iffy to an extent, but still strong overall. His neutral air would be incredible if only its SDI multiplier weren't twice as high as it was in
Brawl, but it begins to link better as the opponent reaches mid-percents. Even so, Lucas can follow his opponent's DI at lower percents to begin with, so it's not too big of a detriment. Should every hit of nair link properly, it can be followed up with a forward air, up air, down air, footstool, or another nair. The real kicker here is Lucas's ability to fast-fall his neutral air to bring opponents to the ground and use its low landing lag to follow up with moves like up tilt, forward tilt, down tilt, jab, or grab. His up air hitbox is puny, but with such small amounts of endlag and landing lag, it's pretty safe to throw out for its good 13 damage. Since up tilt, down throw and dash attack combo into it, it has solid uses besides a safe gamble. His back air is a nice approach option and kill move, given that its spike hitbox isn't too hard to get opponents with on the ledge or offstage if you can corner them offstage. It reaches just below the ledge if you're facing away from it, meaning Lucas will be getting lots of two-frame spikes on the ledge. It, like all of Lucas's aerials, has little enough landing lag to be safe to throw out onstage. Its non-spike sweetspot--yes, it has two--kills around the 120% range near the ledge, which is actually pretty late. His down air is very finnicky, but it's viable as a situational approach. Its hitboxes don't link well, but this move shines in two regards: its ability to lock opponents and its gimping ability, the latter of which works well when Lucas hovers just off the ledge while his opponent attempts to recover. It begins to KO opponents starting at around 80%, but most will either be caught off guard or sent too far down to even consider a recovery attempt--lest, of course, the opponent is using a character with a lengthy recovery. However, most of such characters have slow, gimpable recoveries anyway. Lucas's forward air is a wonderful poking tool which also has multiple uses. As a kill move, it's decent at best. However, this move can also lock with its sourspot, combo its sweetspot into itself up to four times in midair at mid percents (you just took 45%), and poke at opponents' shields effectively. His grab air is possibly the most versatile zair in the game as well as Lucas's best tool overall given that it has only 8 frames of landing lag with its incredible reach. Out of a shorthop, it can lead into a forward tilt, down tilt, forward smash, or even a grab. Though it only does 4% max, it adds up when you're walling your opponent out in conjunction with PK Fire. It keeps opponents away and halts
Lucas's smash attacks are relatively slow, but they still have their individual uses. Up smash is a fairly bad move due to its high startup and ending lag. It doesn't see much use unless the player reads their opponent or gets a shield break, but the move pays off
greatly in both situations with its above average damage output and absurd knockback growth, as well as invincibility on Lucas's head from frames 15-30 (I believe it's for that long, anyway). His down smash actually has very similar knockback growth values compared to his up smash, its ending lag is significantly shorter, and the attack activates 39 frames earlier. The attack hits thrice and gets bigger with each hitbox (though with progressively less knockback per hit). This is a very questionable move to use onstage as shielding only the first hit of the move will mark the shielder invincible to the latter two, leaving Lucas open to punishes. Where this move shines is on the ledge, due to its already-astounding knockback, large hitbox sizes, and its ability to be spammed combined with its practically-nonexistent punishability on the ledge. If used properly, Lucas can
always be safe to throw out this move as a ledgeguard. Lucas's best smash attack is his forward smash, which is not only quicker to start up than Ness's, but is also higher in knockback values than his, killing tens of percents earlier. Lucas has setups into the move as well, the most common of which being zair and down tilt. This move also acts as a means of reflecting opponents' projectiles back at them for 1.5x the damage, which is actually more than Fox's reflector would do. For reference, Ness's frame 21 fsmash reflects for 2.0x the damage, Lucas's frame 14 fsmash reflects for 1.5x the damage, and Fox's frame 6 Reflector reflects for 1.5x the damage. Lucas's reflection ability is middle-of-the-road, but for how safe his fsmash is, it can only be called a viable, versatile move.
Lucas benefits greatly from grabs. Lucas's standing, pivot, and dash grabs are all relatively laggy, as they come out on frames 12, 12, and 14, respectively. They all have moderate amounts of endlag as well (46, 56 and 56, respectively). However, this still leaves Lucas's tether grab as the quickest in the game, which is understandable for its short reach compared to other tether grabs. Even with such boisterous amounts of lag, Lucas won't be suffering from it if he sets up his grabs using zair. After he nets a grab, he can down throw and follow up with any of his aerials--yes, any of them. All of them come out quick enough. Neutral air is the most common and optimal follow up (unless the player is not confident in their ability to follow SDI...or footstool), but forward air is sometimes seen for quick damage--down air is seen as well, but mostly for combo purposes. Back air out of down throw is a common kill setup at higher percents, but the most common of all is his "Mama's Boy" combo: down throw to up air. It begins killing most opponents around 100%, but it can fall apart if Lucas has a lot of rage. If that's the case, the stock can be closed with an up throw (~120%), back throw (~95% near the ledge) or forward throw (~105% near the ledge), all of which have high knockback growth most noticeable within the 130%< range, as the latter two begin KOing from the middle of the stage. In short, all of his throws will be able to kill at some reasonable point, making all of them useful.
Allow me to list some attributes pertaining to Lucas. His air speed is above average (tied for 14th if memory serves correctly), making his aforementioned aerial follow-ups all the more reliable. He has an average weight value at 94 units, is relatively short, and has a passable ground speed. His ability to return to the stage is, in my opinion, unmatched by any other character in the game in terms of distance and variability. Lucas can go under most stages if the player is crazy enough to attempt it, but even without doing so, he has the ability to halt his midair momentum and bait gimps with PSI Magnet, gain distance (whether it be from the blast zone or his opponent) with PK Fire, snap back to the ledge with his tether recovery, or go plain and simple with his PK Thunder 2--which travels twice the length of Ness's. Lucas can fake out a tether recovery by tapping down just before the Rope Snake grabs onto the ledge, giving him a safe mix-up option to recover using PK Thunder 2.
Lucas's 0-death is not as difficult as one may believe. His footstool combos can very easily turn the tides of a match, though it seems it's best fitted to Final Destination. If Lucas counterpicks Final Destination, his opponent may be in for a rough time.
Lucas is clearly a very capable character to the player who desires to learn the full extent of all of his tools--he belongs in Tier 3 for sure. I understand it's not exactly the most comparative essay, but I'll be sure to amend it at a time during which I do
not have a headache.
I should've called upon my dude
Strawbaby
--he knows infinitely more about this character than I do. At least he can help back up/clarify this information.