On the other hand I have to agree with Larian : missing can be an issue. I had no problem yesterday but tonight it was really boring and combats sometimes last 3 more rounds just because everyone missed the 2 last ennemies (party of 6 with 2 companions!)
This could be solved by a robust loaded/karmic dice system instead of completely breaking the core 5e combat mechanism.
Larian took a sledgehammer to a problem that only needed a chisel.
Yea or easier, with customizable flat bonuses for highground and/or backstab^^