The problem with lessening the lag on just aerials, is that it makes aerials better then the ground attacks. It needs to be balanced. A character who's designed to have a balance in Melee favors aerials in practice. Balancing aerials, grounds, comboing, characters, and players is all a very delicate process, and you can't simply lower lag on aerials without unbalancing the whole thing or dragging the rest with it.
Like I said earlier, I feel that people here focus a bit too much on aerials, and by that I mean that people actually do value their ground game.
The problem isn't that the air game is too good, it's that (a lot of the time) the character's ground game is lacking.
I use aerials way more as Wario because I typically don't find uses (on shield) for his tilts (and I never have a use for his utilt, which is just bad design in my opinion) and his jab is uncomfortably slow, so I typically just rush in for the grab than jab once or twice.
Not to mention his aerial mobility is beastly and I freaking love it, so I make the most out of it.
Now, let's take Ike for example.
I would say that his ground game is perhaps the most valuable part of this character simply because his jab sets up for pretty much everything he wants to go for, not to mention two of his smashes serves as antiairs/roll punishes and utilt is actually a useful juggling tool.
But his aerial game could use improvement; it's typically not very hard to punish missed aerials (especially in PM; missing the cancel on his fair or screwing up the timing so the hitbox doesn't even come out will most likely get you killed), and half of them have too much landing lag/are too slow overall to be comfortably integrated in general pressure, juggling, and poking (in my opinion, but I still love him).
But that's just Wario and Ike -- what about Kirby, a character that's generally known for being aerial-focused?
I say that Kirby is a brilliant example of a character done right -- a ground game built upon rather safe tilts, decent jabs, and throws that actually do something.
I can find a use for most of his moves, the reward generally scales well with the risk, and there usually isn't a time where I feel he has no answer.
But, all the same, he has his faults -- he's floaty, lightweight, has a tougher time vs disjointed hitboxes, and is susceptible to vertical KOs.
We tend to disagree on a lot of things, but I'd chalk it up to a difference in personal experiences.
Not every character is gonna be a Kirby, but I would like for every character, or at least most characters, to have enough options to where they have more answers than problems.
Some characters will be off balance when it comes to an aerial game vs ground game (Little Mac), but it'd be nice to have an aerial game that can be comfortably integrated with their ground game to provide a solid and varied offense.