I think it's quite risky to give Summoner a better Physick (with an added Esuna effect) or any more support abilities because Summoner right now is pretty good at a lot of things compared to other DPS. It also has the risk of being too similar with Red Mage. They both already have a Raise and a party buff, only thing unique about both is one has a reliable direct heal, the other has better damage.

Personally, Summoner doesn't need any more support abilities when all of that can be Red Mage's to justify their standing on the DPS totem pole.