I agree and sympathise on most of these points.
Multiple click spell casting for no reason is silly and needs to go, I feel. I can see people mentioning that it's to help prevent you making mistakes, but I've played plenty of games where they don't do that and it does not cause a problem. There's no rush, be careful and know what you're clicking before you click it. Casting the wrong spell because you didn't read what you were clicking before you clicked it is your own fault as a player - don't put that responsibility on the game designers.
Reactions are an absolute shambles and need to be sorted out, along with returning reactions spells (feather fall, hellish rebuke, and I would say shield, but shield isn't even in this game (!!!) how can they call themselves a D&D game without shield?) back to being so.
I'd also like to see more attention to the game's writing, and the cramped themepark-feeling of the maps is also not ideal.