Brawl was made with the average player in mind which is why he took out a lot of things they didn't like. Wavedashing was hated by everyone and no one wanted to see a more competitive Smash. It is pretty obvious that most Smash fans hate competitive Smash.
That couldn't be farther from the truth. No one hates wavedashing. Sakurai purposely kept Wavedashing in Melee. It wasn't something the competitive community discovered first. It was taken out of Brawl in favor of allowing the player to dodge in midair without going into free-fall. Most anyone would agree that not going into free-fall is a worthy trade-off for the removal of the directional air-dodge. Don't mistake preference for hatred. I am however convinced that he took out L-Cancelling to shrink the gap between casual and competitive players.
Casual players don't hate competitive smash. Most would find it interesting to watch skilled-players fight head-to-head. That's the same with any fighting game or...actually ANY game; just look at the prevalence of speed runs of video games on the internet. Casual players don't like fighting competitive player for obvious reasons and no one likes to see their favorite character labeled as bad in a tier list but that's everyone, competitive players included; no one likes getting 3-stocked. If you sense hatred from the Smash bros jokes like "No items, Fox only, FD" then you should learn to take a joke then realize that joke is from 2006 and was started by Competitive Players poking fun at our own game. Times change.
Only people who seem to think Brawl was a disappointment were competitive players. Everyone else likes it.
This is true but only a select chunk of competitive players think that way but with good reason as the vast majority of the disappointing factors in Brawl only affect competitive players. Balancing issues, chain grabs, camping, planking, etc. those are issues that only affect us. In a 4-player free-for-all, those factors mean jack squat with items only making them even less of an issue.
Brawl's biggest flaw affects all players however; the speed. Casual players won't mind the speed drop or at least until they've tasted speed. I've had a 2 different groups of friends, all super-casual players, play Project:M for a few hours, having a blast with it in 4-player 4-stock FFAs with no items on...and then I put regular Brawl back on. In both cases, each group noticed the dramatic difference in speed and stopped having fun with normal Brawl. Now we all just play Project:M exclusively for our FFAs. I still play Brawl from the tourney scene and community.
Speed is fun. Plain and simple. And that is where Sakurai screwed up the most; he mistook speed for competitive factor and the entire game suffered for it. But it's still Smash Bros, so of course most people won't complain about it but again if you give even the most casual players a taste of what Brawl could have been with the speed re-added, they'll agree that while Brawl is still a great game, Sakurai made a massive error.