AST + SCH in 8 man content and SGE for 4 man content.

AST + SCH will provide the best heals and utilities for a party in any 8 man content as simple as that. AST can boost dps, SCH can boost dps every 2 min and will still be the king at shielding due to the new passive we will have in EW.

SGE should be the best in 4 man content with at least a decent party. From what I've seen, a lot of aoe DPS + enough heal to keep any decent tank alive. Not much more to say.