I really think the enforcer just needs to be fixed. It can 2 shot low health classes without a head shot and the slower firing speed and less damage when disguised do not weigh out the 20% more damage.
Also the degreaser is definitely the best flame thrower and maybe should have some more noticeable downsides.
Finally the soda popper seems to always have the mini crits ready. It is not fun to play a scout when he has that much of an advantage.