Interesting build, but I have a few problems with it.
1. Your runes are really only set up for early game success. Late game, they are bound to fall of hardcore unless you have a build set up for late game dominance, which you do not really have
2. As support, there is no reason to max glitterlance first. the slow and cooldown are both exactly the same, so you are much better off taking one point early and letting it sit.
3. Neither of your summoner spells are designed for support. I think you would be much better off with CV or heal instead of teleport.
3. I also don't understand lich bane. Once again, this is designed for pure damage. If this is in there for mana reason, a morello's evil tome would probably be much better, since it gives the regen and the cooldown reduction, which could potentially free up your build.
4. Starting with a faerie charm is infinitely better than starting with a regrowth pendant for support. It lets you get wards early and helps you stay in lane longer, especially if you know how to kite, use your shield, and especially if you run heal.
5. There is a very good reason to max whimsy early. The difference in the ability power increase and the duration of the polymorph are almost irreplaceable.

I have yet to try this build out in-game, but as of now it looks pretty solid. I altered a few things in the masteries to my liking, and the runes could use some fixing, but everything else is sound. +1