If by "deeper", you mean having more ATs and the like, then sure, I can buy that, but Smash 4 is still a bit young, and any ATs that exist have yet to be discovered. Of course, there's a risk Nintendo can simply patch out said ATs, making things harder for Smash 4's deep gameplay, so to that end, yeah, I can buy Brawl being deeper at the current moment.
Okay, so this is a common bit of confusion. No, I don't think Brawl is deeper just because of ATs. I mean the amount of thought that goes in to each interaction.
That's because Smash 4's gameplay is very similar to Brawl's. If anything, it's basically Brawl, but with different ledge mechanics, combo possibilities, and no tripping. Obviously, Melee players who tried Brawl and went back to Melee aren't going to pick up Smash 4 when they know it's similar to Brawl, and one shouldn't blame them. Then again, I don't really speak for the Melee community, since this is just a mere guess.
Okay, so lemme give you a bit more examples here of why I feel Brawl's got more depth to interaction.
This is not meant to start a debate, I'm just clarifying.
There's a lot of general global changes from Brawl to Smash 4. Obviously, removal of ATs is a common theme, but there's more than that. With a few exceptions (Bowser), generally most characters across the board have worse autocancels (for example, Peach, Fox, Wario), and worse projectiles (Falco, Peach, Diddy, Fox, etc). While airdodges may have been too safe for combo game in Brawl- they actually provided a bit of an approach mechanism. You could SH and airdodge to the ground as a fakeout.
With the combination of nerfed autocancels and nerfed airdodges and nerfed projectiles,
jumping is a lot less safe in Smash 4 than Brawl.
There's just a lot less going on in neutral. Snake could have multiple grenades out and remotely control the momentum of the first with the second. Diddy was glide tossing all over the place. Falco was trying to whittle down your approach option with SH double laser and predict how you get through it and meet it with a dash attack or usmash or dair. In Smash 4 though, you see how often people roll away? In Brawl, you could usually have a projectile out to cover the roll option, or position yourself with an autocancel so you can punish the roll. In Smash 4, rolls are a lot better because you're more limited in neutral.
There's just
more happening that the player has to keep track of in a given moment in Brawl.
Also: weirdly, I think Smash 4 has the most shallow followup game (between Melee and Brawl, not counting Smash 64). You hit someone, and either have a guaranteed second hit, or a 50/50 guessing game. Smash 4 has a
lot of 50/50 guessing games compared to Brawl. Brawl would have complex guessing games off of hit; you would could force an airdodge with an autocancelled aerial and punish the end, sometimes, or other times you could position yourself to punish whatever action they used to leave hitstun. In Smash 4, you either can hit them, or it's a 50/50 guessing game. In Melee, combo chases are really complex. In Brawl, there's no combos (this is very bad for game pacing), but very deep followups (they can break hitstun with aerials or airdodge, but base knockback is low so they're close, so if I can position myself to cover all of their aerial hitstun breakers I can punish). In Smash 4, there's combos (good for pacing, encourages approach) but followups are really simple guessing games.
(On a side note: Tripping is conceptually inconceivably stupid, but it's actually not a common thing in Brawl. The average player trips maybe twice per three stock game.)
Interaction-wise, IMO, Smash 4 is shallower than Brawl. However, you don't have to deal with the dumb stuff like extreme camping, infinites (there's at least five characters with dtilt wall infinites, grab release infinites on Ness/Lucas/Wario, Ice Climbers on everyone, Diddy single naner lock, Dedede against a wall against the entire cast, Dedede in place against five characters, ZSS dsmash on Fox, Pikachu dthrow on Fox, etc), tripping, godlike Metaknight, etc. So shallower, but better paced and less dumb.
Hence my analogy: Brawl is a wine that tastes terrible going down but has a great aftertaste, and Smash 4 is a mild wine. Which is better is pretty much personal preference and I know a lot of actually notable players that liked Brawl better.
If I recall correctly, isn't the whole "one-inch punch" from Mii Brawler an OP move, and is the only OP custom move? If so, I can understand banning it. Otherwise, all other moves ought to be fair game, no?
People've talked about banning DK's custom up-B and Pika's custom skull bash as well and a number of notable players feel "not all customs should be allowed". However, it's a slippery slope once you start picking and choosing what should be legal and what shouldn't and it really needs to be all or nothing.
Omni
for some of the vlogs he has released covering topics in smash Smash including Diddy Is Innocent, Overcoming Tournament Jitters, 3 Ways To Improve Your Smash Game, and others. His most recent vlog has brought up a lot of controversy and discussion throughout the community as it is titled Why Smash 4 Will Die. In the video, Omni discusses his thoughts on some of the things most detrimental to Smash 4 right now. Give it a watch!
LiteralGrill
is always up to discuss anything related to Smash. Follow him on Twitter and start a discussion! 
).......
