With the game's current control scheme of clicking where you want to go I can't only imagine playing with a gamepad to be rageinducingly terrible. Maybe with some rework it could be acceptable (but still worse than mouse/kb), left analog for movement, right analog for view etc. But we actually use quite a lot of buttons while we play.
1,2,3,4 Skills.
F1,F2,F3,F4 Consumables.
M,N,H,I,8,9,0 for hero/minion selection.
5,6,7 for minion summoning.
Left/right click.
Tab for score.
In conclusion I feel that playing with a gamepad would be gimped and terrible. RTS' and gamepads don't mix. Even though this is RTS-light.