Try this Raist, pretty much what I run in those rare moments that I specc into bubble.
http://aoc.yg.com/feat-planner?class...336-13,2337-11
Your build is ok but I would take the points out of pillar lightning and symbiotic idol of set and place them elsewhere. In my experience you wont see a large enough DPS increase from symbiotic(I top the dps charts in almost everything I do without it) to be worth 5 points. Unless you plan on using LS exclusively there really isn't a point in taking pillar lightning(I only use LS when being in melee range is a bad idea; I throw out inner charge + lighting cast combos in my spell rotations and to take out people at low health in pvp). Might as well take those points and get a little mana tap return with them. The one point in titanic storm is there to give you some breathing room when you are in melee range, I find that one point is all you ever need. But it is totally optional if you feel comfortable in how your SF works in melee range.