Would adding a Dac improve the sound for my setup?

After looking at your system and seeing your goals, (clarity and soundstage)my advice is to forget the dac, scrap the PS power conditioner and pick up a good power conditioner, such as an Audience AR6, or the 6T if you can stretch. Lower noise floor and overall sound improvement, IMO. Of course I can't diagnose your system without hearing it, but neither can anyone else, so my opinion is as valid/ignorant as anyone else's. Again, IMO, a $1000 DAC is just a sideways move. If you want a real improvement over the AA, you will have to break more eggs than that. At least that's what I've found. Good luck.

Musical Fidelity V-DAC for $299. You can return it if you don't hear a big difference; I think you will. Use a decent digital cable.

Adding the right DAC can improve all the sonic signatures you're looking for. But, like everything else, it is system dependent.
Burson dac is the one I would highly recommend.
There is a 30 day trial for the Burson. I don't think you'll be sending it back though.