Builders are too important

Just because a good builder has the power to change games doesn't mean they need to be nerfed. The reason why your team loses is because not a single person changes to builder to counter the enemy builder, or at least someone who knows what they're doing. If you do this you are guaranteed to slow the enemies down, and if you continue to lose then their team is just better. So why do you think you deserve to win if your team is all knights/archers? If you want to win games not only should you have a team balanced between the three classes but also your players will have to be skilled too. Maybe that good builder will be placed in a team with mostly bad players. Well they can still easily lose without good knights. The nature of random placement in a team based game is winning isn't gonna happen every match no matter how good a single player is.

As for nerfing, builder is quite balanced atm imo. Is a tramp cannon uncounterable? No, build your own tramp cannon. It's not as if it's difficult to set one up before the match starts.