Probably because you have to aim it, they also want to it so no roaming super can OHKO another super as seen here in the Shadebinder section: [quote]One—Winter’s Wrath is still the best Super for shutting down other Supers, and it’s not even close. Winter’s Wrath must now freeze and shatter other Supers twice to kill them. [b]As a general rule, roaming Supers shouldn’t be able to one-shot other Supers.[/b][/quote] Yet bottom tree Gunslinger can one shot any super in the game if you hit them in the head. Clearly OHKO abilities that are difficult to land are exempt from this. The reason Flux grenades were buffed but Fusions weren’t is probably because there’s no exotics you can use to build around Flux grenades. Warlocks have Sunbracers and Verity’s Brow while Titans have Ashen Wake, Hallowfire Heart and Armamentarium. Hunters don’t have anything that improves Flux grenades, nor any way to get more of them. Either way Arcstrider sucks compared to Gunslinger and Nightstalker, having a really strong grenade isn’t going to do much to change that.