Hey, glad to hear that!
Could you send me a picture of the stl issue with supports? I just found out that something weird is indeed happening when you export the die while in support edit mode, I'll have a look at it soon, but perhaps you've found something entirely different :D
Dice blanks - yeah, I got a few requests about that already, I'll have a go at implementing that - but it's a couple of features down the line.
Ctrl+Z - I know, I know, sorry - this small little feature is actually deceitfully difficult to implement. In the future, yes, I'm intending to add it, but I can't say when yet.