Thank you all SO MUCH these ideas are great wow. I definitely think I'll make the first class feature the ability to sacrifice attacks to add d12s to the attack. I THINK I'll go with it being something you'll be able to decide to do after the attack hits or misses, that way you don't invest all your attacks for a turn on a wasted hit. And I think I'll let Action Surge attacks be valid for spending, after all without that a level 3 fighter wouldn't be able to use this feature at all.

The question however is, should I make the other level 3 feature an initiative bonus or a crit range bonus? Also maybe the fighter should be able to reduce their movement for the turn to ten feet to add another dice?