My considerations were quite different.
First, I was already thinking about getting a camera with a wider angle lens. Also, I've noticed significant improvements from generation to generation in precisely the places where the 750Z had problems - mostly with macro work.
But the most important consideration was time.
I will still probably get this one fixed, it's a very good camera for many uses.
I'll also be interested to see how well image stabilization works on the new one. Telephoto was a bit of a problem with the 750Z without a tripod (and I never carry a tripod) due to camera shake. With an 18x zoom image stabilization will be much more important.