TimTuma balance between competitive and fun is subjective, but when is something considered OP? isn't that a bit subjective as well?
It is easier to determine if a weapon is overpowered because you can use data instead of having to settle for all the different opinions and preferences in the community. For example the iron bomber and jag are straight upgrades as they are equipped over the stock weapon 99% of the time because they just do what the normal weapon does, but better and it's noticeable. In comparison the current available sniper, spy and heavy unlocks are all well balanced. In games you can notice that a player has the option to use the normal minigun, the brass beast or the tomislav - but there is no unlock that stands out so much that everyone is almost forced to use it.