I was reading this thread last night, and decided to revisit Leaf Shield tactics. So I apologize for the long write-up.
I was playing Anthers Ladder and got two incredibly simple kills with it, edgeguarding. Some things I noticed (as I believe have been mentioned):
If you're at the ledge with LS active, and they try a get up attack, rolling, jumping, or dropping, LS will prevent them from doing it. I punished a Ness with a back air two stocks in a row with this. LS active, and hold shield at the ledge. He tried to roll each time, and I caught him and backthrew.
Also, LS is hard to use against button mashers. Against fast jabs and smashes, I don't totally advise using it; I played a Mario, and any time I had it active and it connected, he'd just down smash.
I found that the most useful use for it ON-stage, is using Rush to cancel your momentum and land with no lag. Because typically, your opponent is close by, and expecting you to land with lag. Sometimes, I'd use it (against a Fox today) to regain control of the stage.
Use Rush, and as soon as after you land, you activate LS and you land with no lag, run in for a grab. So far, I've found no one is expecting it. I say it's most useful, because at mid-to-higher percents, it led to me getting a grab and forcing my opponent into uncomfortable landings and other shenanigans.
Interestingly, I've noticed my opponents, when offstage, air-dodging leafshield.
However, if onstage, I noticed roll spammers will still get a punish off. Which tells me they are button mashers.
Lastly, I was in the lab last night seeing what Leaf Shield is able to beat, and (I apologize if it's already been mentioned) I found some interesting things. I wanted to particularly use it against the more popular characters.
R.O.B.
In half to most cases, Leaf Shield canceled his Gyro outright. Presumably because of its large hitbox. But I found that to be interesting. I have not faced a ROB to test it in a match, but I will try if I get the opportunity.
King Dedede
I wanted to see how Leaf Shield dealt with D3's Gordo's. And in about half-to-most, it just reflected it right back at him. I say half-to-most, because in training, it kept reflecting them (few did still hit). I did face a D3 in For Glory, and I did get about two or three reflected Gordo's using Leaf Shield. But in the end (Because I was at high percents), I opted to reflect them with the Metal Blade.
Ness
Little use on Ness, aside from a possible gimp. But the hitbox of PKFire is too small for Leaf Shield to effectively stop it. And you really would have no use for it against PKThunder. But I was able to trade with a recovering Ness, which landed me the kill. But it was risky, in my opinion, and you should be ready to tech if need be.
C. Falcon/Ganondorf
Should be a no-brainer by now. The gimping is endless with these two. I did attempt to apply it to on-stage C.Falcon, but was thwarted by C. Falcon's DTilt. So, because of his speed, I'd advise against it, in this matchup.
Sonic
If Sonic is recovering low and near the ledge, this can gimp him. I got one off last night. Sonic was recovering low, and I activated Leaf Shield, after Sonic was hit, he fell doing his FAir animation, to his death. Other than that, I wanted to see if it beat out Sonic's Spin Dashes, which it mostly doesn't. I've found that occasionally, it'll clash, but that is it. It would probably not be advisable, considering Sonic's speed and ability to punish it.
Pikachu
This was pretty fun. Leaf Shield, in some cases, canceled Pika's neutral special. But it wasn't effective enough for me to consider it useful in a match against a live mate. But what I did find fascinating, is how Pika's Quick Attack interacts with Leaf Shield. I wanted to know this, because (I'm not sure if this happens to anyone else), but when Pika players are unable to get in, they will resort to neutral-B to Quick Attack to get in. So, in half-to-most, I've found QA will either clank or trade with Leaf Shield. But at most, it will stop QA in its tracks. Which can either be good or bad. Because if Pika tries to follow up with an UTilt, chances are he will get you regardless. But if you are shielding and it clanks/trades, you might be able to follow up where Pika lands. If I come across a Pika after work (I typically do anytime I'm in FG), I will try and use it.
Fox/Falco
This was necessary for me, considering this is a popular counterpick on FG, when people think they will beat your Mega Man. I was only interested in Fox's up and side special.
In regards to his side-special, it interacts with Leaf Shield the same way Pikachu's does. However, Fox is a little easier (in my opinion) to predict. Where Pikachu can use QA from any which direction -- grounded or in the air -- Fox can only do it horizontally. I will give you a scenario that I had on Anther's today:
Fox was recovering from the side of Smashville, while I had Leaf Shield active. First few times, he went directly at me. Small percentage of the time, he landed behind me, definitely confused, leaving me with a grab. Half-to-most, he was hit by LS and fell below, only into another side-special animation to his death. If they try and go a little below you, to the ledge, there's a chance LS can still hit them, while active, and put them backwards or forwards.
In addition to this, LS does nicely against Fox's up special. I Leafstooled a Fox on FG last night, and just plain confused a player on Anther's today. It will almost do what it does to Falcon; knock them out of the special, leafing you to safely footstool. Or, it just hits them and confuses.
Link/Tink
Lately, for some reason, this has been a tough matchup for me. And admittedly, Leaf Shield is not fully the answer. But I did find it useful, in the following way: I took a stock off of a VERY, VERY spammy Link, last night. And I figured (Because we were down to 60 seconds) that if he wants to camp me at the ledge, I will stay on the other side. So I went to the other side, and took out Leaf Shield, which easily cancels all of Link/Tink's long-range options. This forced the Link to approach me, after about little bit, which led to me eventually winning, with 5 seconds left on the clock.
Bottom line, it is Mega's longest ranged projectile, and against Link that does nothing but throw arrows and boomerangs, it was super effective to negate that. But fighting a roll-and-projectile-spammy Link/Tink still exists, when they have to get in.
In addition to that, it takes awhile to start up, so as mentioned earlier, jumping and activating, or canceling the lag with Rush is the way to go.
Villager
Lately, I've been facing a lot of Villager counterpicks. Naturally, I wanted to see how this matchup could possibly play out. I played two Villagers last night, and used Leaf Shield in one of the matchups (after using it in the lab).
So, obviously Leaf Shield destroys his Lloid Rocket. But after the rocket launches, so does a Metal Blade and even a lemon. So, I didn't think it was that much helpful. However, I faced two Villagers last night, as previously stated. One camped the ledge, and the other one was more aggressive. The one that camped the ledge, via snapping the ledge, and then releasing and using the slingshot, only to return back to the ledge, Leaf Shield was great. LS out-ranges the slingshot, so it was very safe to use. I forced the Villager to approach me, and I won very easily.
The more aggressive VIllager just pocketed my Leaf Shield, the multiple times I took it out, and it negated the usefulness of it, the rest of the match.
Duck Hunt Dog
If you face a campy/run-a-way DHD, Leaf Shield can be safe to activate and throw. I faced a not-too-good but campy DHD and just spammed Leaf Shield. My opponent stopped spamming and ended up just getting wrecked the regular way. But good to keep in mind to how it works with his projectiles.
Samus
Not worth using against her. Trying to out-camp Samus is a bad idea. Leaf Shield won't work on her full charge shot, and lemons explode her missiles. Just get in and zone her. However, I did knock Samus out of her recovery this morning, using Leaf Shield, and the opponent fell to his death. But I don't know that it's really worth it, as I think Samus' up special would come out and hit Mega Man faster than LS would prevent her.
Pit/Edgy Pit
Not really useful. Pit/DPit's extra jumps won't allow you to really get a gimp. And Leaf Shield does out-prioritize his arrow, but most Pit's don't really spam those. So it's not worth it, really.
Pac-Man
So this was interesting. SOME of Pac-Man's fruit would not penetrate Leaf Shield. Primarily, the large ones. Pardon me for not knowing the names, but the green one was negated by LS. The paralyzing one was also negated. And the other one or two large ones were also negated. The key, obviously, got through, every time. Where it's useful? Not fully sure. I haven't faced a Pac-Man in awhile to experiment with, but the ones I have, don't really spam Pac's projectiles.
That's all for now. Didn't try it on Robin, Olimar, Wii Fit Trainer, or even Greninja, as I don't typically run across those. But I figure most of this is known by now, but I figured I'd try and put my own two cents in.
Thanks!