To each his own, I suppose. Never played a PT/Vanguard, but having a 50 Commando I find heat management, in any spec, far easier than rage/fury management.
Anni will not be nerfed that hard. I don't even spec into 100% camo, I prefer the extra point in Obfuscate, so all that will change is in giving me 2 more skill points to use. Kind of a neutral change imo, at least in PvP (Losing 100% in PvE is a significant change, but I can live with it).
Carnage and Rage are getting buffed, by not by a huge margin. Actually, with the way Ataru works right now on PTS, it's a nerf to Carnage as well, but Devs have already responded that Ataru isn't working properly so hopefully that's fixed.
Anni will still be a viable tree, and I still expect most Marauders to be Anni. It'll just make Carnage a more viable build. Rage is still meh.