Will Scratch have to be shut down (temporarily)? I'm only asking because it seems that Scratch is having many bugs/issues right now, and it would make sense if Scratch shut down so that problems can be fixed without constant complaint or people quitting Scratch because of all the bugs.

Scratch has been in a far worse state and managed to stay up.

No, there are no plans to shut down for repair. We understand the known bugs are annoying and we are actively working on fixes.