Having played my fair share of summoner so far, I can honestly say that the Bane nerf I feel is huge. Not to summoner but to its usefulness as a skill. Painflare and fester are more useful, dps wise than Bane will ever be.

IMO i think that main should be brought back to its original 1 target + 2, (without using an aetherflow) and sustain brought back by using 1 aetherflow, and either healing a percentage overtime, (for pets) or being a buff or heal for Team Mates. for example (use use Sustain on a Tank, each time they take damage for the next X seconds, it is reduced by Y percentage. If used on a pet, it will heal X% of its life every Y seconds.

For Healers it could be, Each dps dealt by the anointed healer, will be released after 3 seconds in an aoe heal, centered on the healer.

etc, etc.