Vegas Steakhouse that's not particularly formal?
What do you recommend for a steakhouse on the Vegas strip that's not "jacket and tie suggested" level of formal?
I'm not aware of any steakhouse that suggests jacket and tie. That standard is reserved for only a couple of top dining spots (none of them steakhouses). Most of the better steakhouses will specify something like slacks and a buttoned shirt or perhaps polo jersey; even that won't be strictly enforced.
My favorite steakhouse is CUT, if price is no object.
Last summer a friend and her daughter were in town and I visited them at their hotel. I didn't know they were wanting to go out to anything fancy for dinner and was just wearing shorts and a nice but not fancy t-shirt. They felt like going to a steakhouse but I was a little concerned due to what I was wearing. We called a few places and they all suggested at least a collared shirt and preferably pants. Finally we called the Golden Steer and they said "The only thing we suggest is that you wear a smile", so that settled it, we were going there. We did and everyone loved it. The food was excellent and the service was great.