In the interim, as a GM, I was just going to use those nifty editable PDF character sheets - they're springing up now for most popular RPGs. I'd have a copy and my players would have a copy. Also, we have a potential trio of relative newcomers for our games so having a copy to hand will make it easier to help them too.
I'd love to see some sort of editable in-game Character Sheet (attached to player tokens themselves?), but when you consider each RPG usually has it's own sheet, even if it uses the same or very similar system to other games, whilst others are completely different, I can see that being be tricky to implement. Either that, or use a completely blank template that you can fill in with each stat/skill yourself.
Another alternative could be a blank space that players and/or GM can fill in with the Block-of-Stats method that most gamebooks give NPCs?
But other than sheets, allowing players to handle the HP, auras and journals of tokens assigned to them would be useful.
I think that the most common ones should be quite easy to implement , be it a Wizard of the Coast or White Wolf or Shadowrun game for an example , but what they could do is simply allow the GM to set up/write a character sheet for house rules or less common games and then simply give out the sheets to his players , I'm pretty sure it wouldn't be that hard and I really think it's one of the most important things to implement for the release .