More trouble than it's worth, is their thinking I guess. Granted, one could call that laziness..
Either way, I don't see why it'd be hard to stick Dean in the Tops and just have him sit there with afew new lines of dialogue about the ridiculous walk back to the Mojave and the crappy radio DJ (in his words, not mine). Maybe he could even get up on stage and sing every now and again. They don't have to be companions, even if that's preferable..I guess either way, me and Dean's, um, shall I say, conflicting viewpoints, resulted in him having a much harder time coming to the Mojave anyways..