To your final point I will again say that this is not a table top RPG, it's not a pen and paper RPG, it's a computer RPG, a video game, it's going to take time to kill enemies, you aren't just rolling a dice and the outcome is set, that's random luck, not skill and almost all gamers want skill involved so no, we don't need a 'kill-all-enemies button'. As I said at the beginning, you are just going to have to accept that the genre has evolved along with the technology and you're going to get a very different experience than you got with BG2. However the game will most likely ship with difficulty levels and like DOS2 (and other games) have a story mode where fights are so easy they're over much faster.
The problem is not about difficulty at all. When I play a fantasy adventure I want to play sword and socery and not pit shoving and barrelmancy.
For me the current combat system is utterly without soul and fun. It is a silly puzzle solving game paired with spamming of the same spell/action again and again.
I wouldn't care if they threw the D&D 5e System comletely out of the window and created something that I can enjoy.
But currently the bare bones implementation of the 5e combat system in Solasta is about 10 times more engaging, tactical, interesting, challenging and fun for me than the Baldurs' Gate system.