Before I moved to the South I (a non-Southerner) did not feel comfortable saying "y'all". But "you guys" seemed sexist. I have since spent a decade in the South and I have not picked up much of the dialect, but I definitely say "y'all" now.

"W'all" would be nice to have. I guess it's not a thing because it sounds too much like the things that separate rooms.

You, y'all (small close group), y'all all (larger, further group), and "all y'all" — Southeast Texas (coastal) dialect form that showed up about 25 yrs ago. I suspect it might've been there all along, but only became acceptable at that point?

Another 100+ years, and this'll be some solid grammar.