I'm finding it just fine, teamed with a WHM and healing with my fairy.

The best way I have found of using her is in steady mode, when I need group healing I use Rouse + Fey Illumination, this gives +40% and +20% healing, then she blows Whispering Dawn automatically, (Although I wanted her to, just working with her AI) and everyone gets a HoT for 300+ a tick, totalling 2100+ for everyone over time. Its not bad. It gives me 55'ish seconds to put her back in it before she auto uses it again anyway, which I normally have time to do.

Eos needs some tweaks though, no argument from me.