Since its called the Wither "Storm" and that the blocks spin around it like a tornado, could you maybe make the wither storm control the weather, like in the later stages it would put the whole world in a permanent thunderstorm? This may or may not have been shown in mcsm tho, however there are various thunder sounds that play whenever theres a cutscene that involves the wither storm (example, the cutscene near the end of episode 2

well, it was in mcsm, and this would be a very good update, so yeah

I outlined my opinion on this here: #228. While you're suggesting global weather, with the darkened sky feature coming soon I feel this is redundant and would be kind of annoying (atleast in my opinion).