I understand that many games nowadays try to mouth feed their players who unfortunately have been "casualized" ( from quest indicators in rpgs, removal of complex mechanical concepts, to respawn timers for jungle creeps and many others). I do not believe this change is for the better however, and I do not say this out of nostalgia.
As for Sona I honestly do not understand how the perception "she is boring" or "people do not appreciate her" came up, and as for the "she is weak" I attribute it to the fact she got nerfed over and over again since she was released. So this perception in my opinion is enforced to people as a "self fulfilling prophecy".
And about the general riot's philosophy ... I believe dota 1 was a more complete game than lol is today. Even in the first draft of lol where many of the dota aspects were preserved the game had a slightly bigger variety than now e.g. gankplang could deny a minion but later this was removed because it did not fit the game. lol is enforcing a champion/item/playstyle uniformity that I find weird.
The game is more boring than it could be not because the champions do not have abilities flashy enough but because 90+% of the games a guy goes top, another goes mid, top go bot and the last one jungles with similar champions played every game. Do you know how much flame some that want to run urgot, poppy, mid Sona can get. No denies, no tri-lanes, no creep stacking, no river runes, no level one baron, no buybacks, no losing gold on death, no day night cicle, no high ground advantage, dodge pretty much removed from the game... and when a champion has a unique attribute in the game like auras we remove it to make Sona even more similar to Mami... thats my take on the direction this game is heading