The problem with all those crazy glitches is that they require HUGE commitment. Sure, Lucas does get impressive raw distance, but he spends a lot of frames in lag when doing those ATs. MK is a character who can control the ENTIRE OFFSTAGE ZONE. If he doesn't suck, he can and will punish and gimp you on read/observation.
I consider myself an EXCELLENT player at recovery in specific, and yet I do get killed consistently offstage by characters with good edgeguarding when using Lucas. He just doesn't have a versatile enough recovery to really consistently make it back safely. For this reason on top of other problems, Jigglypuff also solidly beats him.
At any rate, probably the single most important thing to fix on Lucas is the fact he can't juggle crap. His inability to really set up a juggle into anything hinders him a lot at winning aerial exchanges, dealing damage, and setting up kills easily. He just can't threaten you in any realistic way when you're far above him. He has some decent ways of getting in and poking, but they all lead to nothing, and his more reliable stuff has pretty poor damage output, and he's very bad at comboing off of throws, which actually gives him one of the weaker grab games in Brawl on top of having below average grabs in general. Speaking of his throws, the angle on F-throw should be lowered, since his F-throw just sucks and doesn't do much of anything useful.
And lol no, it's easy to kill Lucas by staying out of his range. Like Ness, he has some of the worst range in this game, and his reliable approach/poke tactics really don't hurt you a lot.
Change of topic:
I don't like the change to Falcon's U-throw. I think it's very unnecessary and it changes the feel of the character too much. One of Falcon's better points is that he's very good at punishing high altitude airdodges, and that's kinda where the charm of U-throw is. Putting them up high above you and then forcing a high altitude airdodge.