Overkill is subjective. What is it exactly? I'd bet no one can really define it. But I'd look at it like this...a 308 or 30-06 will kill deer just as dead as a 300 PRC will in 99% of situations a hunter will ever encounter. The 300 PRC was designed for doing one thing very well, and that is shooting very long, very heavy-for-caliber high BC bullets out to very long range (which is why you see most 300 PRCs with very fast twist rates). If you are long range hunting any kind of animals, then the 300 PRC is right up your alley. If you don't do that and just want it because it is cool, well then maybe reevaluate your firearm choice. Any other 30 cal from 308 and up will kill deer and elk very very dead out to 500 yards or more. The bigger you go, the faster and flatter your trajectory, but I feel you reach a point of diminishing returns somewhere just north of 300 Win Mag. After that, yes ballistics and energy are better and higher, but the end result remains the same.
As for the meat damage thing, you will get more meat damage as you get a higher energy cartridge, but as has been said, sticking with a mono bullet will mitigate that somewhat