So, your thinking appears to be that Cruz made a brilliant choice with Fiorina?
Have you ever played cards? Sometimes when you play, you end up having a losing streak. When that happens, you've got to do something to try and break it up. You do not know what will work, so you have to try things.
Sometimes it works, sometimes it doesn't. One thing I have found out is that if you do nothing, you remain in your losing streak.
Cruz is now facing an uphill fight from a former New York Liberal Democrat turned "conservative." There isn't much that he can do at this point, but i'll not fault the man for trying to do something.
Doing nothing to change the status quo is a certain failure.