At first glance I thought it looked good, but Johan is the anchor of your pitching staff. Having Johan and Billingsley together makes a huge difference. If you make the trade your top two will be Lee and Billingsley, which is not even close to as strong. Davis has been questionable so far, and I have heard of a lot of people getting frustrated with him, and even dropping him.
Although, the upgrade from Holliday to Soriano is really nice, I am hesitant to say take this trade because you are giving up Johan, and also ending up with Chris Davis. If you could switch out Davis for another solid SP, then I would say go for it. It just doesn't seem like the best move considering your roster.