RE: Opinion on the 223 as a deer hunting cal ?
It is certainly a capable caliber provided it is used within its limitations, and with proper bullets for the game at hand. While a few states have chosen to deem it verboten to use on deer/bear, I see no ethical/moral problem with using it what-so-ever... you just have to accept and realize what you are up to... and also accept that there are probably better choices.
I've shot a bunch of deer with a .204 Ruger.... never had any of them take so much as a step.... but I'm not shooting at moving targets from a kneeling offhand position either.... what I use might as well be a vice.