I've found Kirai quite fun to play. Her summoning does take high cards to use effectively (just like most other summoners), but there's no TN on Sundering, which is a pretty good attack.
Don't forget that she has Entwine Spirit, which lets her cannibalize a nearby friendly Spirit for +2 Ca on an action (which all her base actions are). If you have some Seishin or even a weakened Gaki nearby, that can carry you through a bad or mediocre hand reasonably well. Plus, you can discard those low cards to bring out her Ikiryo if she or her crew start getting attacked, so it's not as if low cards are utterly useless for her.
Between Of Pity and Wind, Manipulative, and Lost Love, she's actually fairly durable so long as you don't end up with Justice or a Viktoria in her face (which is honestly going to ruin just about anyone's day). Her Swirling Aether upgrade helps with this quite a bit (and gives her another use for low cards).