I owed it to Brawl to give me a great segue to pick up on "Smash Basics". I learned a whole lot about spacing, zones, strings, and options/critical thinking without having to be frustrated with my then-terrible tech skill (it still is a work in progress, but at least I don't flounder and have messy inputs 90% of the time).
Imo, there were a few positives to the game. I felt the gap between perceivable mid and top tiers was closer than in Melee (where I felt that in Melee the surprise has come within the gap of Low-ish Tier and High/Top, we're seeing a lot of development of M2, Yoshi, Pika, YL that have become more prominent as niche/pocket picks) where spacing and the RPS effect were more centric in Brawl (they still are very important in Melee/P:M, but in Brawl that was basically all you had to make interactions happen). Oh, and also Brawl Doubles were much more dynamic. You had some very interesting gimmicks that were actually proved to be very effective, things like Snake C4 "delivery" combinations, Bucket/PSI Magnet duos, and my personal favorite, "Anubis" Lucario stock manipulation. A lot of stupid and matchup-ruining flaws singles had like easily exploitable recoveries, ridiculous grab release/chain-grab exploitation become a lot harder to use to the fullest extent in doubles. I feel Project M Doubles also follows this similar trend, with a rich roster that enables some things to go on besides space animal(s)+Peach/Marth/Ganon/Falcon/Jiggs/Sheik, where you basically would have little variance in strategy besides strong pressure and maybe strong stock tanking, edgeguard, or raw KO power. I know MK was a pretty dominant force in Brawl doubles too, but I felt the there were more flavors of strategy developed that proved to be effective.
That being said, I'm a bit glad that Melee and P:M are doing well, they feel so much more rewarding when you get into them and apply yourself, and I feel that Brawl was a great transition into these games. I enjoyed the ride that Brawl provided, but I've moved on (partially because our scene in Brawl died pretty hard), and frankly I've been burned by Brawl pretty hard in ways that really shouldn't be optimal (being timed out/air camped is the worst feeling in the world), especially when your character is relatively slow. I feel like I didn't have quite the same complaints most Melee players did, as my character actually did have true combos (but they hit like a whiffle bat lol), and was pretty fun/visceral whenever you made the comeback or hard reads. Although I have to admit, I have no idea why they made his recovery so awful (seriously, a predictable, hitboxless curvable jump?)