There are a few changes SCH could stand to receive. Won't talk about pet ai, it's been covered. Everyone knows it is broken and fixes are needed, like a toggle feature for fairy skills. But here are some ideas to throw out there.
Succor doesn't need a potency buff, but rather a mechanical change. Succor could remain at its current 150 potency heal/shield and work fine if they did something like the next Succor cast on a target that is shielded (from a succor spell) to consume the shield and add the shield value to the new succor's healing that is being cast. In other words say I cast succor and it heals for 200 and shields for 200, casting another succor on a target that has a succor shield up consumes the shield and adds that 200 point shield to the new succors healing to make it look like 200h/200s -> 400h/200s. That would give us the AoE heal we so desperately need while remain unique and different from a WHM.
Eos should have her regen spell cd dropped to 30 seconds.
Another change we could stand changes to Selene's buffs. Currently all they do is add 30% spell/skill speed based on your skill/spell speed stat TO your spell/skill speed stats. If you or the players being buffed haven't heavily invested in spell/skill speed stats, Selene is complete garbage. What I would rather see from her is a true 30% haste buff that has both skill and spell speeds rolled into one handy spell on say a 2 or 3 minute CD. The now empty slot she has could then be turned into a single target resource regeneration buff that is uncastable on the owner of the fairy and restores the resource the target is lowest on. Also, scrap her Embrace and instead make it an atk the does splash healing based on the dmg it deals to targets near whatever she atked. Obviously make it a weakish atk/heal. I have no idea what to make of her interrupt. Haven't had a need to use it and the CD on it is rather hefty so dunno what to make of it. But anyway, she is a utility fairy, lets make her utilitarian shall we?
And last but not least, can these damn fairies be put on a completely separate GCD from us?