Personally, for me, I alternate between Disintegrate and Incinerate since her Molten Shield really isn't needed until the DPS can get close to you without dying.... which should be NEVER!!! XD Also, the damage from Disintegrate, combined with getting the mana back for last hits with it and it's range, make it, in my opinion, better to max first than Incinerate. Incinerate does more damage, but Disintegrate gives out more harass and better early games; this is by staying in lane longer...

Just a thought.

I think you should up your disintegrate by 1 or 2 more levels, especially during your laning phase. this allows much easier last hits and more painful harass with your stun, unless they are dumb enough for you to land incinerate.

why mp5 and CDR ¿?