Well, to be frank, Warlocks are warlocks because of their insight to the traveller and the darkness. I know its a bit a cliche but, warlocks are the wizards in MMORPG, that also includes healers too. The attunement of grace makes sense, it finally enables the warlock to have a healer class. During D1, Fireborn Warlocks were more or less the wildcards for fireteams, providing a second chance. Song of Flame, however wasn't as potent so it never got to see as much action (I do rock with it personally, no fun not using the super). Titans, are of course the tanks, defender makes perfect sense. Provides a safety net as well as an over shield. Perfect. Hunters are what their name suggests, nightstalker with shadow shot suppresses enemies and therefore allows bonus damage. It does support the team, by [b]debuffing the enemy [/b]and [b]buffing weapon damage.[/b] Conclusion? Other than titan's melting point. There is each a subclass which allows the Hunter, Titan and Warlock to either buff their allies or deal a debuff. Some classes do it better than others. If i were to exclude Well Of Radiance Warlocks, the so called mages don't have much support options other than their rift. Running a warlock is actually disadvantageous to the whole fireteam. But I concur, if you wanted was a copy and paste for hunter where they magically heal everyone because of course, they happen to specialise in magic just as well as warlocks then go ahead. Hell, may as well give warlocks the Ward of Dawn too if that is the case right? [spoiler]This is just my opinion, likewise I don't see the fast, solo guardian providing shields, or health back. It just doesn't fit them. In that respect, I shouldn't be seeing warlocks doing something out of place as well.[/spoiler]

I mean, code of the commander is a definite support element In terms of the super, since the shield boosts damage. That isn't full support though, I agree. The others should've gotten one

Technically, all three have a subclass that can be seen as a support class. Sentinel's Code of the Defender can give overshields to surrounding allies with their melee, not to mention the Ward of Dawn. Hunters have the Nightstalker's Code of the Pathfinder, with Vanish in Smoke and Heart of the Pack. But I think I know what you mean by your question. My theory is it has to do with the Sunsinger's super, Radiance, more specifically the Song of Flame node. That was, in essence, a support option for Sunsinger, rapidly recharging grenades for the Sunsinger and his/her allies. Maybe Bungie wanted to give Warlocks back the option of acting as the team's support. Again, this is just a theory.

Ah Hunters have teather and titans have sentinel? Whats your problem?