One of the things our group found problematic from the playtest materials was the damage-on-a-miss ability of the fighter. Against low hit point critters it could be interpretted as scaring them to death, which is amusing to think about. While we would prefer to just toss, one option might just be to declare no kills on a miss as an addendum to that ability.
I can see a place for the rule based on how I view hit points, short version - they represent the avoidence of a lethal blow until you run out of them, and not actual damage. This reinforces the need to avoid a kill on a miss, and even the designers have said they are in line with my idea of hit points as opposed to them actually representing wounds.
Here's hoping this is something that will get worked out in playtesting.
The good news is that most of what we are seeing is a mish-mash of optional rules.