After the 10th round or so those are the only types of SP's I draft...high risk/high reward. I would put Burnett on that list, and in H2H leagues you could probably put Carpenter down there...since you would be more concerned about him being ready for the fantasy playoffs...particularly if your league has 2 or more DL spots. Prior is more of a question mark, but since he's also high risk/reward I would include him...but not as someone you should count on, but rather as someone to think about grabbing in round 23+ and see what happens.
I understand what you're saying about the pitchers having to be ready to go in April, which I would agree to be the case for roto...but H2H makes high risk/reward guys more valuable IMO, because you really just need your team completely healthy for 6 weeks or so near the end of the season (assuming you make the playoffs
). I agree there is little point to drafting safe SP's in rounds 10+ and think you'll be pretty successful with your strategy.