It's "y'all", a contraction of "you all", not "ya'll". Which makes infinitely more sense than "yinz" which is apparently derived from "you ones" or something like that?

I also find that 'dropping of to be' sounds completely unnatural to me. It sounds like something I'd expect a non-native speaker to say.

My personal favorite English change is the cot-caught merger.

Of course, all of my preferences make sense because I grew up internationally or in the south - I wasn't caught up in the cot-caught merger and I picked up y'all because there has to be SOME second person plural!