Does TA experience for wide range of classes improve future job prospective?
All else being equal, then more and more diverse experience is better. The problem is that all else will not be equal. 

If you teach the same course over and over again, then that course will become better (up to a point) and you will have to invest less and less time in it. So you will probably get better evaluations and have more time to do other stuff like research, at the cost of having experience teaching a narrower set of courses. If you teach more diverse courses, you will show a more diverse experience at the cost of getting somewhat worse evaluations and less time for research.

However, in my field the differences between the two aren't that big: if you are new to teaching, you'll spent a lot of time preparing regardless of whether you teach that course the first, second, or third time. The improvement in quality will be there, but that does not necessarily mean that that will translate in better evaluations. The extend to which a more diverse experience pays off depends on what is expected in your sub-sub-sub-discipline. The person that is in the best position to advise you on that is your advisor.