I'm on the opposite end of it. I love the changes to Heavy and Special ammo. I hated PVP before and never played it as a result. I play it everyday now in addition to my other Destiny activities.
Well my issues might differ from others but my problem with heavy ammo is that it gives you so much notice that it's coming that it gives the other team time to just run over and super the shit out of your entire team. That's all I do now. Save my super for heavy ammo and then nova bomb like 4 people. It's fucking stupid. I'm sure the meta will change but right now that's what I do and what it seems like people may eventually catch on to. I also liked it more when it didn't show you where the heavy ammo spawned. Believe it or not a lot of people still didn't know the spawn points for heavy ammo. But that's just a minor gripe.
The special ammo I have a much larger issue with. I wasn't one of those folk that ran around with a shotgun or fusion rifle, so it's nothing about that (I also never complained about those people because it wasn't that hard to deal with). One of my problems is that they changed the spawn points and I already had them memorized... whatever, I'll get over it. The other problem, which is my main beef with it, is that it completely fucked up my build. I play a gunslinger with almost max strength and discipline and I play with the scavenger ability along with Young Ahamkara's Spine or whatever it's called or the Symbiote helmet. I was able to constantly chuck tripmine grenades along with always having throwing knives available. I can no longer do that because I can't pick up any fucking ammo.