Overall, I like the WP Keyboard with one exception... I'd love to have left/right arrow keys for moving the cursor without having to mess with moving the cursor up in the text, which i understand is even different on 8.1 than currently on 8. I know some people hate this idea, but it's something I've sorely missed since having to switch to these virtual keyboards instead of physical slider keyboards.
Something like this would be nice

It's not perfect as the space bar is pretty small, but no solution is going to be perfect on screen. Even if arrow keys were available on landscape mode, and went away in portrait mode, I'd be happy!
http://forums.windowscentral.com/attachments/windows-phone-8-1/59299d1394561940-wp81keyboard.png