zompist bboard

A thought I had during my nights work which I wanted to see what you all think.

If a language were to have a very rich pronoun sysem including alot of sub versions of each given english pronoun for some reason and lets assume it already had personal agreement on the verb or bipersonal agreement either works. Would the rich pronoun system make the language more prone to get rid of the personal agreement because the pronouns is used often anyway as they divide things in such a fashion or would it stay behind and both work side by side over time?

The rich pronoun system may help allow the agreement markers to be lost, but in general, it will not cause them to be lost. As a guideline, subjects and objects are things that many languages are perfectly happy to mark twice in the sentence, though of course they don't need to.