FULL DISCLAIMER I'm not a Dota 2 player myself. I've somewhat tried to get into the game recently, but still haven't done a full PvP match yet. I'm still not 100% sure if I'm gonna go fully into Dota (Probably not), so please don't be too hard on me for my lack of knowledge toward it
I've had some strong feelings toward this question, but for League of Legends, as that's by far my more knowledgeable game. I won't go into my specific details on that their tho. What changes to Dota 2 do U think are needed most, but are also so fundamentally massive & impactful, that at that point you might as well just make a completely new game? From what I know, a lot of current, massive issues with the game are more-so on an "outside level" (Extreme Toxicity even compared to LoL, extremely unforgiving to newcomers, Esports for Dota are a complete joke now, etc) but is there anything on a fundamental gameplay level that people are having strong feelings against ATM?