The default rocket launcher is still the best tool for the soldier, same with the default sticky gun and flamethrower.
All of those things are true, except for the flamethrower. The Degreaser, for the most part, is superior, since the axestinguisher puts out far more damage than the flamethrower could ever hope to.
In addition, the default revolver for the spy is insane and an amazing weapon. The default minigum is awesome as well (although, due to Tamislav being overpowered as hell right now, not as useful as it once was before the patch).
Most weapons in this game are SIDEGRADES, which means you don't get any better or worse, you just get
different. Most of the time, at least. Some weapons, due to certain imbalances, are strictly upgrades, like how The Enforcer's downside of .5 longer cloak time does NOT affect the Dead Ringer, making it a straight damage upgrade for Dead Ringer spies.
Usually, most perceived OPness or UPness is simply new players being new players, except in a few cases. The Heavy is most definitely overpowered right now, and the pyro is most definitely in a very bad spot, at least in higher level play (in low level they demolish people). Many people also will say the Spy is either supremely overpowered (they're new and don't understand spy checking and how spies work), or supremely underpowered (they play spy and simply wade into the enemy lane and wonder why they get spy checked).