sounds fine to me. just remember that you will still need mechanical brakes.
worst case scenario, you might have to add a fan to the esc if you want to gear higher. i have seen this esc used before in 1/5 without any problems.
They say a good mechanic only needs 2 tools - WD40 & Duct tape. If it moves, and its not supposed to, duct tape. If it doesn't move, and its supposed to, WD40.