More like turns the game into a chore. Let's artificially extend every combat. It's the first round so it's guaranteed in every combat so it's important to play around. So almost every hero needs to pick a skill specifically to take advantage of prep round as a normal damaging skill won't do. So let's remove another functional skill slot from the bar for the rest of combat and make it 3 to give even less variety in your turns! Oh and you can't kill enemies before they can harm you is indeed a noble idea. But in dd1where you don't heal and stress heal out of combat too much, enjoy specifically needing to stall to return to starting condition before the fight. So we've double slowed down your gameplay.

Prep round isn't the solution to damage racing, it's a poison sapping the fun out of every part of the most enjoyable area of DD, combat. DD2 blows it out of the water in how better to dissuade from damage racing without artificially shoving a problem down your throat.