Cool idea with such a great potential! I'd suggest to rebind navigating to Shift+WASD (Shift — directioning mode, WASD — choose direction, optionally — vim-like navigation). This will allow player to keep hands on the alphabet section of the keyboard. Another way is to somehow limit the randomness so that the letters around the player's cell are always different. You could also +scores for correct inputs and -scores for incorrect ones. And if the letters you enter form words, player get even more +scores! Then you could introduce different backgrounds for the cells, which would provide different bonuses, like in Scrabble. And then you could make all this greatness PvP as well. :) C'mon! Go on! You could turn this prototype into a very cool typing game!