While I generally agree with your premise, I do always feel somewhat lacking while playing Engineer since everyone else has something, “special” (career ability.) For me, the Minigun feels more like a high maintenance/high reward version of a 3rd weapon than a “special” thing for my character. I realize that the invisible talents/passives in the background are what truly makes each character, but in practice and for immersion, active abilities really take the cake and entertain users/audiences.
Depending on how similar the gameplay of Darktide and Vermintide 2 end up being, I’m not sure I’d really dig all the characters only being able to play with melee and ranged weapons. Sure, there are consumables, and maybe that and the sustain of such consumables or map/objective specific temporary rewards through talents and choices can be manipulated to feel great. Maybe we even have a situation where consumables are Career-unique, or change to the career-unique consumable depending on who picks it up? A somewhat related example is how the 3-slot-grenade-inventory mechanic for Engineer ended up being a tiny yet huge addition at the same time.
I think I feel cooler in a Vermintide/Darktide game where I have abilities and talents in addition to weapon slots and consumables…rather than a Doom guy with 15 ranged weapons and no career ability to speak of. Not to hate on Doom, cause it’s fantastic at what it does! But I play Vermintide because I prefer the experience and group play that it offers.
Here’s an example of a hybrid final solution - The Imperial Guardsman could have a melee weapon and a ranged weapon. He can choose a 3rd weapon, melee OR ranged from the specialized weapons armory. (All weapons for all careers that come from the “specialized weapons armory” have different mechanics, such as dangerous overheat, high cooldown, require multiple users, or cause the player to be completely stationary, etc.) In addition, he would have a career ability: heal shout, group move speed shout, throw a cluster grenade, highlight all enemies for increased damage, dispense incendiary rounds to the team, etc.