I think we need more types of nades personally. A freeze nade that slows (instead of freezing solid), black hole, and gas (damage over time and blurry vision) are a few that come to mind. The first two shouldn't be that hard in my opinion and the third one probably isn't that difficult to make either. Spicier gameplay would come from these.
- Freeze grenade - slows people in the radius with direct hits being a 100% slow duration TBD
- Black hole grenade - spawns a black hole just like the trait does, could have a different radius if need be.
- Gas grenade - would blur vision, make players cough and take damage over time
- Shrapnel grenade - would have an initial explosion less than that of a frag but would inflict bleeding damage
- Acid vial - kinda like in left 4 dead where a circular area is marked, the effect could be anything really, high damage if you stay in it is what I would propose. Could even be made a T weapon and have zombies spawn, and they are attracted to players that were affected by the nade?
- Glue nade - direct hit would slow players and would also leave a residual area of slowing (could last for a decent amount of time) anyone that walks in it
- Laughing gas - players in the gas laugh and cannot shoot normally and instead will occasionally laugh really hard (think a witch's cackle) and just randomly discharge their weapon. (Damage could be credited to nade thrower to discourage RDM)
- Bird nade - a swarm of bird NPCs flock in and peck nearby players
I could keep on going but you get the point, there are many ways to add more types. Some may ideas are a bit ambitious but I don't see why they couldn't be added.