Whenever someone does a thread like this, you get a ton of different opinion and a lot of the things I've read here are not crazy.
People just weigh things differently and that's OK with me.
CA used to require a great than .23 cal for hunting - now its simply "centerfire" with bullet rqts. For a lot of our coastal "rat" deer, a well-placed .223 will do just fine. Accent on well placed though.
For me, I decided to build a 6.8 SPCII as my deer/pig hunting platform. Although I have seen guys get to take 20 minutes setting up on a sleeping pig at 100 yards (and still pull the shot
) I have never had an opportunity on a pig that wasn't moving. I decided that I wanted something with more oomph than a .223.