Have you ever as or against Lucas? He's got worse priority than Jiggs and that saying something. Like seriously, all the lucas can do is sh forward b wavebounces or however you say that. His approach is seriously like the worst in the game. How are you planning on killing someone? You might be able to get some percent on your opponent with forward b... maybe... but then how are you going to land something that will kill. His smashes are slow as balls, his tilts don't have that much range, and the only aerial that has some range is his bair (which sends downward). Not to mention his recovery sucks as well. Sure its a lot better than ness's but it still sucks. Up b-ing leaves you dangling there for a bit and it makes you an easy target to hit. You can also just attack the pk thunder and it gets rid of it and you die. So basically as long as the Lucas' opponent is patient, Lucas is an easy as hell matchup.
What? Bad priority? Sure, it's not the greatest, but the hitboxes of some of them are spaced away from his body; that would be his dair, his bair, and his fair. You can air-dodge them, yes, but honestly, whose aerials can't you air-dodge in this game? As for only bair having range, you should look at his dair and his fair. They have range as well. Fair might be one of his worst aerials, admittedly, but it can kill.
Sure, his Usmash is slow. His Dsmash is also not very fast, but it's designed to punish spot-dodgers. I would think that already having one of the strongest D-smashes in the game that lasts for a while is in need for slightly less speed and a very small hitbox for behind. His f-tilt has plenty of range for its speed, and it's not easily punished. Fsmash kills and comes out fast. The range isn't the greatest, of course, but
I don't see why he should be automatically thrown at the bottom of the pile just for having a less-than-stellar approach. Zelda has an even worse approach, yet you don't see people ragging on her daily for it. Lucas can pressure most of his opponents; he's supposed to force THEM to approach. He can still approach with a FH'd dair, his nair, and with PK Fire. He doesn't have the best approach again, but again, he's not designed to approach. The mere fact that he DOES have approaching options + his baiting is good enough. Also, don't underestimate his wavebouncing. That keeps him safe from people who air-dodge his PK Fire, and it closes in the distance between the two of them, thus shortening Lucas's oh-so-awful approach.
Lucas has a technique where if you PK Fire + double jump, you shoot FAR in the air. It's not very hard to do the PK Fire + double jump technique, and it shoots you so far in the air that you won't need to use PK Thunder after that to recover unless you get smacked back out there. He also has a tether. If you must PK Thunder, you aim for the ledge - he sweetspots the ledge.
Also, good luck attacking that PK Thunder. Few characters in this game can pull off an attack at an angle where he'd PK Thunder (below the stage) in the speed that he can blast himself. I laugh when I see certain characters with good aerials try to jump in and attack it, only to get punished by the tail and then hit with the actual attack in some instances. It's very hard to counter.
I'm probably being biased here, but at the very least, I know that Lucas isn't as horrible as you make him out to be. I don't expect for you to agree with me, but I wanted to defend one of my favorite characters. By no means do I believe he's anywhere near the top, but I don't think he's horrible at all. Sure, from anyone else's perspective, I'm probably talking "nonsense", but what's a guy to do when his character's being ragged on?