"..Getting everyone in a region together a few times a year is a really interesting idea. It will feel like a SQL Saturday or other event when you know everyone will show up. I can see this generating some excitement. Especially if those days are different from normal workdays.."
If it's a once per year regional get together, then they might better make it span multiple days, sort of like a PASS conference. There could be a slate of presentations by employees to showcase their projects, lunch & learns, and after hour parties. Larger corporations could even reserve an entire hotel with a ballroom and maybe even have a celebrity host the thing.
But when an employer announces they are going full remote - at this point I don't necessarily think it should be considered carved in stone. I'd suggest folks wait a year or so to see how the policy pans out before making a big life change like purchasing a home in another state - based on the assumption they can always work remote going forward. Because, at the end of the day, an employer will rewrite policy however it suits them in terms of practicality, productivity, and financially.
Consider that the shift by many employers to work from home will actually drive down rental costs for office space. Many employers may see that as an opportunity - notwithstanding the preference of their employees.
"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho