I'm not sure I agree – who do you see as the volatile guys? Crick worries me a little bit, but it could just be spring training. I don't see the reason to doubt RichRod much at all.
I've only seen him one time, so maybe the numbers are deceiving, but Liriano looks ok outside of one bad one. I think it's more about taking the gamble that he's refined it and will be mostly effective in the bullpen. Kingham is the only one who can really give length when necessary. Burdi looks like an exceptional plus arm to me, so if Crick is fine, we'll have 5 very good weapons and some questions in the middle of the games. I agree that the 5th starter situation is a bad one, but I don't think we're set up for the flirting with disaster we had last year when we had Smoker and Neverauskas (who, btw, has quietly put together a solid spring).
My sense is that this is the best initial squad, as much as I'd like Kingham to just be the starter with Lyles in the pen, and that Holmes is going to undergo some real retooling as mid-relief in AAA to serve as a backup in case Kingham and/or Liriano can't hack it. I have some minor worries, but I'm pretty confident with the backend, and will be moreso if I see Crick return to his dominant form when the games matter. Of the options, I saw Burdi the most this spring, and he looks like someone who will utterly dominate even if maybe have a bad game or two as he settles in.