I just used an entire wind team with only Hleela at 120 the rest 99. Hleela basically healed the entire time maybe got 2 attacks in. Focus on the slimes/flan first the poison and AoE damage is annoying.
The esper is great for Oberon, but the VC is probably not as useful as Titan for most compositions. If you're pairing him with Aileen, OK, maybe it's a different story ... but why would you pair him with Aileen?