That's great to hear about the green check and about the shift key, as well as about upcoming Copy+Paste. Might I ask how the copy paste is going to be implemented? (If you just implement normal selection, you can just add a Ctrl key and support standard Ctrl-C Ctrl-X and Ctrl-V combinations, as well as others like Ctrl-Y/Ctrl-Z for redo/undo respectively, etc. If going that route, see next paragraph)

Personally, I think a Tab or Ctrl key might be more useful than smilies, but that's depending on the user. Alternatively, the Tab key could easily be mapped to one of the 123 layout keys, instead of having a dedicated key.

Speaking of which, perhaps the 123 button could work like the Shift key as well - single press to pull the next key from the 123 layer, double press to lock to the 123 layer - so shift+123 makes the next letter from the 123+shift layer, but the rest of the following letters are the normal ones. 123+shift+shift locks shift but does only the next character from 123... Actually that's not necessarily as convenient for the users, so you could put 123 key behavior (and while you're at it Shift key behavior) into settings as well, between the way they work now and the way you're intending to implement the shift thing. (If you make a Ctrl key, the same thing would probably be great for that too.)