Clearly you seem to disregard facts and attempt to pass off your opinions, which are askew, as facts that need to be done without having done your own research.
WASD movement? try smite, you'll be back i promise.
The development teams in charge of reworking champions and making new champions are different, it has been stated by reds before that it is harder to rework older champions and takes more time than to release a new one.
It is harder to make another competitive game mode because champion balancing comes into question. say if you make a new gamemode like capture the flag, fast champs and champs that have distancing abilities, nidalee, hecarim, etc, become op in the new game mode, but the nerfs to their movement speeds may leave them completely unviable in SR.
Their priorities are right on par, this game is the most played game in the world, they are doing it right to keep the community this massive. You may not like that this game doesnt have as many competitive modes, but every other game in this genre only has 1 map and fewer champions.
TL;DR Get your facts straight and compare other games in the genre, you'll love how riot is handling their game.