Destiny 2's new gun system relegated the shotgun, sniper and fusion rifle to the heavy weapon category. The reason seemed to be balance. By Rise of Iron, shotguns had proved so impossible to balance that Bungie outright removed special ammo from spawns in the Crucible. The result was a more balanced game, but not a very interesting one.
The trend for Destiny 2's post-launch updates, however, have trended in the opposite direction. The 'Go Fast' update turned speed back up, and Warmind's various overhauls turbocharged exotic weapons. Balance has been put on the back burner in favor of fun.
This September, Bungie is axing the new gun slot system entirely. It's not quite the same as the old system, though. Rather than a Primary-Special-Heavy system, special weapons have been folded into the primary slot, albeit with their own special ammo. You can run two traditional primary weapons, or two special weapons. Or three shotguns. After getting to experience the new 'Gambit' mode with the new system active, I'd actually argue this is a superior system.
I'm biased, obviously. Months ago, I argued that specials should just be folded into the primary slot, and that we should just have two primary slots. They'd be balanced by reintroducing special ammo, but exclusively for those weapons. In theory, I believed the freedom to mix and match weapons of more types would lead to a more interesting game. While many regular readers agreed with me, I got a lot of pretty vitriolic criticism over the article after it was shared to Facebook groups and abroad. I love discussing ideas, but that idea in particular seemed to have a lot of haters. So, seeing Bungie end up going this route is more than a touch cathartic.
Speaking of catharsis, the new gun system feels great. My first match of Gambit, I opted to go with an auto rifle, a shotgun in primary, and rockets in heavy. It felt as good as it did in D1. But, I also love the hand cannon/SMG combos opened up by D2. Forsaken gives me the option to play either way. It's exactly what Destiny's power fantasy is about, and I'm glad Bungie went this route, rather than just rolling it back to the D1 slots.
In sum, we now have two primary slots and a heavy slot. Special weapons can go in either primary slot, but require special ammo, which drops at around the same rate it did in D1. Special weapons include shotguns, snipers and fusion rifles. You can run dual primaries, or dual specials. It seems that there will be a heavy shotgun variant, sitting in the heavy slot and eating heavy ammo. This may mean that snipers and fusions will be similarly split, although there are a few details I'm waiting on before I judge.
For starters, heavy shotguns/snipers/fusions should behave substantially differently from special weapons. I think The Legend of Acrius and DARCI deserve to sit in heavy. I don't think Hawthorne's Field Forged shotgun or the Aachen Lr4 do. It could be that only exotic shotguns/snipers/fusions have heavy slot variants, since many of them certainly pack the punch to deserve that categorization. It's also possible, albeit unlikely, that special weapons can be free moved between the heavy and primary slots.
Whichever way that detail pans out, I'm a fan of the new system. The new Gambit mode is fantastic, and the new freedom from weapon constraints had my guardian tearing through enemies like I've never seen. It's the best of D1 and D2 combined for something much better.