Force-A-Nature doesn't remove double jump, the Sandman does. Force-A-Nature can be good, if you get right up to most classes they'll die there and then if you unload both shots. If the Sandman was rubbish then it wouldn't be banned from competitive play...and you don't need double jump to do well as a Scout.
Bonk!, however, is crap.
Bonk!, however, is crap.