Term for "unnecessary diversity"?

Solution 1:

One commonly used term is fragmentation.

It is employed to describe, for example, one of the difficulties of programming for Android, because there are so many versions of the software, and so many different hardware configurations. With Android this is both a strength and a weakness, but fragmentation is the term that captures the negative side.

Solution 2:

A common phrase with regard to too much diversification is bad is summed up in:

Too many cooks spoil the broth.

The concept here is that if too many people are working on the same project, it will spoil the result. "This cook thinks the recipe needs more garlic salt." "This cook thinks the recipe needs more kosher salt." It results in a big salty mess.

Another idiom of the same vein:

Too many chiefs

It's probably better related to the people who want to be in charge of things; for instance, those who want to establish new standards and at that, more new standards than is necessary to effectively govern.