Eh....I think my short, big picture answer is that you need 27 outs and probably shouldn't upset the apple cart too much trying to get them.
I don't think I agree with the premise/motivation of your idea though, and relatedly thought about chiming in last night to say that Counsell's management of the starters is probably one of the few things I would give him credit for (opted not to because I'm contrarian enough as it is). I think what's implied in your idea is that the later innings are more important than the earlier innings (and that we have a couple 'strike throwing young guys with gas' capable of going multiple innings). If you go with the idea that the 9th inning is the most important*, I don't want a tiring starter on his third turn through the order on the mound. Plus, what happens if the opener or the starter goes sideways? You've kinda committed to using them both (or going full bullpen game and the ramifications there). The three batter rule has obviously made it harder to pick and choose matchups but your idea takes away a lot of the value of a guy like Leiter. And, ultimately, if we had a couple 'strike throwing guys with gas'....we probably wouldn't be in such search of solutions.
* The counter to this, that all 27 outs are equally-ish important, is that you want your best pitcher, ideally fully rested, going up against their best hitters, and the best way to guarantee that is to have him throwing his first pitches in the first against the top of their lineup.