It's some time we don't see Gamesboro (maintainer of the OUYA port) in the forum (the forum reports he was last active on 20 December 2013).
I dont have an ouya.. I knew that OA OUYA edition had some kind of support for keyboard and mouse
[1]. But I think that Pelya (the one who maintains the Android port, and gives support to Gamesboro when needed) mentioned there are 2 USB keyboard bugs yet unsolved.
IMHO, I would allow mouse aiming only when playing locally or when playing on PC servers: if I were Gamesboro, I would disable mouse aiming when playing on Android servers (to do not be unfair against touchscreen users).
However, if Gamesboro does not re-appear, there is not a lot we can do about OUYA...
Main OpenArena OUYA Edition Thread:
http://openarena.ws/board/index.php?topic=4822.0[1]I think that mouse support was defined as "limited" time ago, but I'm not sure about what kind of limitation.