I am not up to date with what support/heals are effective in WvW. Before I left last, Firebrands were very strong for all of the boons and stability they provide. Tempests were strong in zergs where they could hang in the back. In a small group, I am not as certain. I don't recall seeing a ton of support druids in WvW. I know that before I left, healing Engy was a thing in raids. I could imagine it being fun in WvW as well. A barrier/heals/support scourge could be really fun in WvW. Not sure what other healer/support classes could rock in WvW.
If you haven't already, @Astriel identified some strong builds for WvW.
Perhaps other active WvWers could comment? Not sure who is active in WvW atm.
RaVem