Do not want. We have a sympathetic "supernatural creature faced with the human world" character to provide the other side of the Sam 'n' Dean "humans faced with the supernatural" story. His name is Cas. And no matter how the writers (and the haters) try to character-assassinate him, his chemistry with BOTH the brothers is irreplaceable. We don't need the vampire side of that coin, too.
Now if Show can convince me there's a place for Benny in this scheme, without forgetting that Sam and Cas both are already Dean's blood brothers, and without shoving one aside in favor of the other, I'll give it a chance. But knowing this show, and knowing how difficult a time it has knowing what to do supporting characters that look ready to last for the long haul, all I'm seeing is another flash in the pan. A character they bring in and desperately try to make sympathetic, because it's easier than dealing with the messy, hard-to-write and far-more-interesting established characters and relationships they already have.
Prove me wrong, Carver & Edlund. There's a lot riding on tomorrow night's episode. I really hope I come out of it with a different taste in my mouth than I've got right now.
(Ty seems like an amazing guy who's doing his job, btw. Just because I don't see the utility for his character doesn't mean I have anything against him. Act your heart out, dude, and change my mind!)