We must be talking about two different people. "Studs" are great when you need to get your horse laid, but in pitching terms, an ACE is a stud. Someone the team can lean on to break losing streaks. That is NOT CZ.
If he doesn't have his best stuff, he's a train wreck. No one wants that as their ace. An ace has to be someone that can pitch, not just throw. If CZ doesn't have exceptional location and power, he melts down, or more common, will give in and hit too many bats.
I've only seen him pitch a handful of times, (but I follow the nutjob's every start as he's on my miserable fantasy team) and in none of those outings did he impress me with anything but power. He had a habit of shaking off the catcher repeatedly, especially in big (critical) situations. This breaks the rythm and more importantly tips off pitches to the batter. In a big game? Fuhgetaboutit! Once he starts missing locations, he tries to overthrow. Just my opinion, but when it comes to big games, the physical follows the mental.
If that doesn't convince you, (here's one bet I will agree to) I'll bet my nuts that if you asked any opposing team who'd they rather face in a game 7 (from the Cubs), it would be CZ first, second and third, followed by Wood then Prior. That's highly logical. A good team, with a walk, a bloop and a blast would have CZ out of the game in the first inning (mentally anyway).
When you add Jose Lima (especially) and then Pedro Astacio to the discussion, you've completely lost me. Mental midgets and trainwrecks when the heat is on.
I'm a big fan of Krod, but he's a short reliver, and without a lead, he may never play. In addition, what experience does he have closing out big game situations?
The answer is very very little - if any!