I was thinking about that, since the first game had exactly that, but it seems more like the game is going for giving different strengths and weaknesses through actual weapon variety instead of through upgrades and add-ons.

Plus it more easily creates more weapons to sell in the warbonds, so cynically, I don't see them bringing per weapon upgrades back, as much as I'd love that too. It would make balancing much more difficult, too

Deep Rock has overclocks that do things like these. My main issue with the game is how the armor piercing works though, all weapons should damage armor but armor piercing weapons do more damage to it instead of base weapons just bouncing off.

Dataminers have already found models that look like attachments and dialogue lines related to "class specialization perks", so I think yes, there will be modifications and specialist roles you can equip.

I'm personally hoping for better scopes and improved stocks for recoil reduction. I'd really like to see helmet mods to add zooming, upgraded target marking, and maybe even synthetic vision like thermal for spotting bots through fog.

Specific weapon upgrades are a bit of a detriment, due non-upgraded weapons feeling worse. An system where you can attach parts you've bought to any compatible weapon would work around the issue.