Heh, the balance we were striving for was 'easy to maneuver' with mouse movement vs 'easy to aim' with key movement, but we definitely need to make mouse's weapons stronger -- on a post-deadline build, we've experimented with making key's projectiles bigger, and that's helped a lot with making the modes feel balanced
Swapping control schemes at a fixed time interval was an idea we considered, but we figured it wouldn't be necessary if the modes were balanced so that each mode was better in certain situations. Then again, auto-swapping would force the player to think about positioning a bit more carefully, so that's worth implementing and playtesting ^^
Thanks for the thoughtful feedback!