I guess I just don't understand the problem. I know that with some of the modern-design bullets for the .223, it's a quite-adequate deer cartridge. But the general caveat has to do with the size of the deer, the type of shot and the range.
Not a lot different from the way I've used my .243 with the 85-grain HPBT bullets. Neck shots, cross-body heart/lung; no angling shots--and, mostly, a 200-yard limit.
But if I'm hunting where long shots are probable and particularly if the deer are generally larger than in central Texas, out comes the '06. IMO, reliable penetration for angling shots becomes a controlling factor.
You're from BATFE? Come right in! I use all your fine products!