It's more that competitive players fear the game won't be FUN to take seriously if it's dumbed down. 95% of the Halo 1 and 2 pros hate Halo 3 with a passion, but they're still the best at the new game. Brawl *could* turn out the same way if Sakurai removes all the depth from behind the scenes. Competitive players inherently understand that, and it's what they fear.
But, what's been dumbed down??
-Characters have less lag time..
-Heavy characters have boosted stats and armor when attacking..
-Top tier characters have been balanced and low tier characters have been improved..
-Gliding has been introduced..
-There are now more ways to grab the ledge..
-1 character has to switch movesets every 2 minutes..
-1 character has to pluck plants to even perform smash attacks..
-Getting Final Smashes, unlike regular items, actually takes skill and strategy..
-Items, like the Dragoon, have become more complicated..
Summons perform more complicated tasks, like Devil and Manaphy..
-New techniques like footstool jump, crawling and wall-clinging have been introduced..
-More characters can wall-jump..
-To the above two points, not EVERY character can crawl/wall-cling/wall-jump..
-1 character can't use her final smash without changing movesets..
-1 character needs to let time pass by before one of his special attacks does any damage..
-More heavy characters have good recovery(Charizard, DeDeDe)..
-Shielding cannot be spammed due to increased speed of withering..
-Most-to-all clones have been Luigified..
-The variety of character speeds is greater..
-At least 32
unique movesets available..
If anything the game has become MORE complex..!!
Are wave-dashing and L-cancelling so fundamentally important to the game of Smash that they outweigh every new addition to the gameplay that's been added??
For the loss of 2 advanced techniques we've gained a plethora of new abilities that can/will open the gates to many more NEW techniques..
Or is it just because now ANYONE has the advantage of less lag and such that competitive players are upset? Why is a move that was not intended to be available, like wave-dashing and L-cancelling, more special than moves that ARE supposed to be in the game?