Food for thought: the system is broken if traits are so worthless that players see no benefit in upgrading past blue weapons. Whether you like the nerfs or not, the 1.0.1 patch definitely pushed the trait system towards being redundant and a waste of code that should probably just be removed from the game.
Given that Fatshark put the trait system into the game in the first place (as well as in Vermintide 1), I would tend to argue in favour of making them more useful instead of nerfing them. Perhaps that means traits need to be more creatively designed in order to be satisfying to everyone. There are some traits that are really smartly designed (e.g. the potion trait that gives you all 3 but reduces their duration by 50%.) These are similar to TF2’s alternate weapons in that they have tradeoffs, opening up alternative playstyles without producing a net benefit in most situations.
By contrast, some of the traits are just lazy and provide an unambiguous benefit: all three of the non-weapon equipment slots have a “25% chance to not consume resource on use” trait, which is worse than almost every other trait, but better than no trait at all. Traits like this should be removed. They’re the ones that make you want to re-roll, and therefore cause getting ‘perfect’ traits to feel obligatory.
If an FPS is to survive long-term, it needs to have lots of replayability. With or without PvP, that means it needs a high skill ceiling. In the MOBA genre, the skill ceiling is generally a product of whether or not the game has high-risk/high-reward gameplay. Heroes of the Storm is a flat, easy, casual game. Dota 2 is not. The key distinction is that characters in Dota are very specialized, which makes good teamwork very necessary to balance out their shortcomings. If we want Vermintide 2 to last, balance decisions should favour making heroes more distinctive, not homogenizing them.
If that doesn’t appeal to you, remember that Recruit and Veteran won’t vanish just because the higher skill difficulties exist. Maybe traits and high-level talents should be disabled on Recruit, if you really want to keep the playing field balanced. (The devs already put a cap on power level for lower difficulties, so this would be consistent.) That way there will basically be two games, one for casual players who want uniform experiences and another for more extreme and diverse playstyles.
Finally, the scoreboard is probably a big reason why people think the game needs to be homogeneous. It suggests that players who get few kills aren’t doing as well as others, and fosters the kind of thinking we’re seeing here. If a player is tanking, or focused on picking off elites, their numbers look worse, and they feel compelled to focus on slaying hordes instead of fitting into a unique role that synergises properly with the rest of the group.