Resolving interpersonal disputes and guessing how much you have to pay someone to get them to stay, and software architecture, are two (three?) totally unrelated skillsets.
You don't need to "guess" how much to pay someone. The market dictates that. HR has pay bands. Raises are always in a narrow band. I don't know what kind of disputes you're talking about.
If you ask any manager - describe your responsibilities succinctly, they will most inevitably fail to do so.
I can imagine a company that had pay bands so narrow and bonuses so small that managers had no tools to reward high performers, and although I agree that it would take away a lot of what allows managers to do their jobs, I don't think that is the usual situation.