Phillips is a top-10 bat at 2B (going by RARP), he might very well be the best defender in the game at 2B, he's great on the bases and he's got the sort of high motor this often listless squad needs more of.
Frankly, I don't think you could get back a better player for Brandon Phillips than Brandon Phillips. If you got equal value, then you're no better off and if you miss on that deal then you're digging this franchise into a deeper hole.
Plus, Phillips is pretty much the only reason I watch Reds games these days. Without him this would be a soul-crushingly boring team.