Hunters have some very good grenades. In addition to the ones you said.. vortex, incendiary, arcbolts, and spike grenades are very strong in PvP. Voidwall is still good but not exactly strong by itself. Really the only weak grenade on hunters is the flux, but for good reason, stickies were grossly OP on every class in D1. Spike grenades have a slight learning curve but once you learn to hit walls right you can finish off people behind cover easily. I can't speak on PvE strength. I'd agree that titans have many strong grenades but I wouldn't say that Voidwalker grenades are powerful at all. Really the best one is Vortex and the hunters have that too. Scatters only work on direct hits and axions... well axions are quite depressing right now lol. Any hunter dodge will kill their tracking, sprinting in one direction will outpace them in a second or two, even just being close to cover will cause them to bounce harmlessly into it and fizzle out. Lastly, grenade-based hunter exotics are [i]very[/i] good. Shinobu's Vow by itself is grossly good. Titans have Ashen Wake, but they still must land a direct hit. Warlocks don't really have an exotic that creates an insane throwable grenade.