Not a very credible OP--sorry, bosoxmal--but a good discussion. I agree with the "no ace" judgment, but also think our rotation right now is the best it's been since the first half of 2014.
Despite having watched many, many games on TV, I don't consider myself an expert on pitching. Nevertheless, it seem to this uneducated eye that other teams have starters with good breaking stuff and we do not. Price clearly relies too much on his fast ball and does not have a changeup he can rely on. The same applies to ERod. Wright's success is predicated chiefly on the fact that he has a great breaking ball and on good nights uses his fastball sparingly. I think Porcello mixes his pitches well and haven't watched Pomeranz enough to give an opinion. When Buchholz is good, he throws a lot of different pitches--fast ball, cut fast ball, changeup, curve, and I think a slider--and he puts them in the right spots. Price and ERod both have changeups, but can't reliably put them in the right spots. Kimbrel has a great fastball, but I think he would be hittable if he didn't also have that knuckle curve (or whatever you call it).
And this. How many of you remember that time several years ago, before 2013, when Nava, maybe a rookie, faced Verlander with men on base and got a single off a 100 mph fastball, which of course he hit to the opposite (left) field? I am convinced Nava would have had no chance except that he was sure that pitch was going to be a fastball--I think it was a 3-2 count. That's what I think happens to our starters too often--they rely on the fast ball and become predictable. Wright is predictable too. In fact, very predictable. But that darn knuckler is still hard to hit when it is really working. But when it isn't, when it's missing and the batter can bet on the fast ball, then Wright becomes very hittable.
I watched Sandy Koufax pitch, once, in Philly. Great fastball, but also a great curve that dropped off the table. And he had, finally, great control.