He's a subpar defender and an average bat, with less years of control and between him and Salas, cost more money. Bourjos is younger, an elite defender in CF and probably puts up 3-4 WAR without even having anything better than an average year with the bat., with a better than average year with the bat, he's in the 4-5 range.
I just think they could have found a 2 WAR 3B and a decent pen arm for less than a 3-4 WAR CF, but a big part of this is probably the Angels completely undervaluing Bourjos more than anything.