Nah, you really don't need a mic. Learn to play the different roles, synergizing with the team as much as you can. You'll find that as you learn DAMP a solid team working together know their roles, so mic is really not needed.
As for action, the thing is DAMP is really like ME3 MP, simply in RPG clothing. It is fast paced, like ME3 MP was. They are similar in that fashion: ME3 SP allowed for pacing combat and issuing commands (micro-mgmt), yet ME3 MP had no pause function, just fast paced action. It is no different in DAMP. DAI SP allows for pausing and micro-mgmt, but MP is fast paced action.
If you could handle ME3 MP, there is no reason you cannot do so in DAMP as well. It is simply a filter you've created in your mind producing imaginary and unacceptable differences. Shift your perspective. Look at the similarities between ME3 MP and DAMP. At a foundational level they are quite similar. Don't let the different "costumes" fool you into thinking otherwise.