Yeah, Link and Lucas aren't really fairly comparable like this. Lucas's kill options are worse than Link's because Lucas is far more mobile than Link, has was faster and more reliable damage racking options (Link's jab is decent, but it's nowhere near as solid as Lucas's, plus Lucas has things like ftilt, dtilt, dair, and nair to which Link has little analogue), and Lucas has a fantastic recovery while Link's is overall the worst in Bbrawl, bad to a point that it not only makes him bad off-stage but he has to carefully control his on-stage game to avoid being hit into unrecoverable positions (kinda like Olimar).
And yes, Steeler is correct that the fact that Link's up special is far more unsafe than Lucas's fsmash. This isn't to say Lucas's fsmash is safe on block or anything, but Link' up special is usually punished on block or whiff with the defender's most powerful attack, assuming that attack isn't something truly ridiculous like Warlock Punch. This point does matter significantly.
The general point that Link and Lucas are completely different types of characters is the main thing here though. Lucas is somewhat speedy and, while he does not have bad KO options, is really more defined by his excellent damage potential. Link is a strong zoner who is very disjointed and very powerful, but he's kinda sluggish and has serious issues with aerial combat and basically no off-stage game. I don't think expecting similar things out of these two is very reasonable.
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Speaking of Link though, let's go a somewhat different direction. Has anyone been using Toon Link? From what I've seen, he's still good and in some ways empowered by the greater diversity (and his greater reliability on smashes), but it's hard to say since he's definitely far less popular than his twilight self (and most people seem to think he's a worse character too).
And since people are mentioning Falco, I would point out that Thinkaman tried to stir the pot on Falco with little success earlier. The main question I have with Falco is how his matchups look now that those silly chaingrabs are gone. They just kinda dominated Falco's game before so I don't find this particularly predictable.