Yes, grenades can be used at the start of quests like scrider to kill off the npcs that spawn near him. The same can be done if the players know the fight and shoot the npcs themselves right at the start, which would kill all the npcs within pretty much the same amount of time while not taking up weight and an equipment slot that could be used for meds or mags.
While rockets can be fun to use to do splash damage to grouped up npcs there's no need for them when dealing with bosses and npcs are usually killed before they can even get a chance to group up enough in the first place. Most of the time when npcs are grouped up is when someone is luring them away from the other players so they can focus just on the boss. The person luring them, avoids killing the npcs so they don't spawn near the boss again unless it's a npc that causes trouble like the big guys in broken golem.
The bosses and npcs that can be stunned can also be stunned just as easily with a normal dagger or by bfing. If your main goal is to finish as fast as possible though, it's less optimal to stun them because that's one less person shooting.
SMG/pistols/revs can all be used to kill npcs that are far away and do so quicker than an MGs but become less useful when sustained damage is needed which is why I said they could use weight/damage/capacity changes to make them a bit more useful.
I do agree SMGs are better than every rifle in their current state and I do use them along with my MGx2 as well at times. I've also used pistols and revs in the past as a secondary in scrider to deal with problematic npcs that are across the map from me.
The main reason I made these suggestion was to unclutter the drop table and if we're lucky to get revamped version of other weapons that are not completely up to par.
Edit: One thing in my opinion that could be done to make everyone happy is to remove less favorable drops from the most played quests, but have them still drop in every other quest. The only downside I can really see with doing this is that it may split up the community a bit too much.
