It should be used with Soldiers, since crit rockets are pretty devastating if the Soldier is any good. The Soldier is also the perfect class to go around the corner and blast the shit out of everybody and everything, not a Heavy or a Demo. People should also Uber Pyros more often, people run in fear of a Uber Pyro that destroys the sentries and burns people at the same time. Medics think that Ubering a Heavy is best option for offense but its actually one of the worst (Heavy is defense).
About the vote Crit On/Off, crits are a good part of public TF2 gaming, they may be unfair in clan matches but they're fun in public servers, I wouldn't get half the bat kills if I there were no crits! Heavy also benefits from this and Soldiers with random crit rockets. I have never seen a server do this so I say no.