I would love it too to hear Sweetie Belle sing again, though, it will take her a long time to get her cutie mark and she's going to be the last Cutie Mark Crusader who will get it, because she needs to overcome her stage fright first to realize her talent for singing. And this takes time, it's nothing that disappears over night and it needs a lot of discipline to get rid of it.

But just hearing her sing again like in Season 1 would already be lovely. <3