Age is a MAJOR factor in evaluating minor league performance. You can't gloss it over. A 28 year-old pitching well in the minors is not nearly as impressive or as easy to project forward to the majors as a 24 y/o or 22 y/o or 20 y/o doing so. It's somewhat less of a factor at AAA because there are a lot of older AAAA type guys bouncing around, but it's still a big deal. But his last two seasons at AA are utterly meaningless in terms of impressing via stats. It's no different than Urrutia raking at AA as an older guy.
Yes if you are talking about "prospects" but that's not exactly what Drake is. He is in the sense that he doesn't have ML experience, but he's older and is more or less ready to be tested and either kicked to the curb or used. Like I was saying before, don't look at him as a prospect - piece for the future, look at him as a cheap guy with 2 decent/good pitches that if he can hold his own, then awesome, and if he can't you aren't out anything.
We are talking about a replacement level BP arm here basically. You are saying that you don't think they are worth giving a shot and because they are older or whatever you are holding it against them, but I'm saying it really doesn't matter cause we are talking about completely replaceable parts, and it's better trial and error with them until you find some that cheaply fill out your pen and save you money.