All the talk you here about smash 4 is the closer to melee it is, the better
That's true with one thing, and mostly true with another - Tripping and hitstun coding. Tripping (randomly) adds an unremovable layer of luck to the game, and when someone loses off a trip, they literally just lost to the RNG.
The hitstun coding is because of combo love. Removing the hitstun coding error that made hitstun attack and dodge-cancellable a short ways into hitstun will make the game have more combos, which is generally agreed to be a good thing. It does however remove momentum-cancelling (unless the error is reimplemented so that it only applies when you've sustained a certain amount of knockback - this will admittedly place more focus on gimps and KOs near blastlines though, so it seems unlikely).
To discuss other mechanics:
L-cancellers are mad for two reasons: 1) the L-cancelling practice is now useless 2) if they don't autocancel it has more lag - they want the ability to have less lag, but Sakurai doesn't implement it. It does add no cost/benefit analysis to choose to do it or not, but it also made things like Link dair (and Ganondorf) somewhat usable.
Crouch-cancelling made some moves nigh-obsolete and provided strategies that buffed the potency of some characters. If you don't want moves that are nearly useless (Marth dancing blade), need to make CC not useful, or else pick which moves can be bad at low percents, limiting low-percent options. I won't offer my opinion beyond this.
Wavedashers are mad for the same first reason as L-cancellers, and it also means they feel movment is more limited. I prefer the Brawl airdodge (or Minus airdodge) because it makes juggling slightly more tricky and getting onstage a bit easier - it makes the bait and punish game more important. Fox's Brawl Minus airdodge is the best of both worlds, but unlikely.
Edgeguarding is harder in Brawl (not undoable) and flow-chart like in Melee. Take one's pick at to edge mechanics. I like not getting gimped every single time I'm offstage with a space animal, but some like how favored the edgeguarder is.
Some like fast falling speeds. This is literally the only reason (besides hitstun issues leading to fewer combos) Melee is "faster", yet Brawl is by no means slow, as the judgements are arbitrary (and Snoic is faster than CF in Melee I believe). Some think Fox Hyrule 64 is slower than Brawl, others prefer that infinitely to Brawl.
Melee vets say it's more balanced because MK, ICs, Dedede, and Falco (to a lesser extent) [and others to a lesser extent], but Melee has Fox, Falco, Marth, Sheik, so... and in each, there are only a few who can deal with them all (Snake, ZSS, Diddy, Olimar, Marth, Pikachu, for Melee it's Peach, Jiggs, and ICs sort of... CF/Ganon has Fox/Falco problems, Doc and Pika aren't in the best of spots, Samus can fight spacies...). There's a bias in their statement because they assume having a few even matchups for all is balance, not overall cast viability (you have to remove more characters in Melee than in Brawl to make much of the cast viable - 3 in Brawl, 4 in Melee, in my opinion at least).
I like Fox as is, both for practicing Melee techs (heh) and because I think it's a somewhat sarcastic salute to Melee - I also find his current build rewarding to play as, and he's unique. You also don't even really have to wavedash, given the ability to cancel Fox Illusion at various parts of the attack, but I think it was a good idea on the part of the devs and it feels Minusy, not like PM. Just my opinion though.