For the record, I'd have built it like this:
Gnome Wizard 4
Str 8, Dex 10, Con 14, Int 19 (+2 race, +1 level), Wis 16 (+1 level), Chr 13 (+2 race).
Feats: Improved Init, Leather Armor, Toughness, Durable
AC: 16 + Magic
HP 52
HS 10 (+13 hp/hs)
Orb of Imposition
For powers focus on two things: 1) Things that create areas that damage foes when they enter them and/or start their turn there, and 2) Things that push foes around while damaging them.
So Cloud of Daggers (benefits from orb power to extend it) and Thunderwave (pushes for 3) for at-wills, Icy Terrain (though Grasping Shadows from Dragon would do better for this), Flaming Sphere (it's border squares are essentially like a zone of damage), Fire Shroud (benefits from orb save ability), Stinking Cloud (great zone of damage), and Spectral Ram (push 3 and knock prone).
Magic items should compliment this set up of creating areas of enter/start damage, and pushing things into those areas. So for example an Orb of Insurmountable Force (AV), which pushes as an encounter power along with one of your other powers. Probably also Veteran's Leather Armor (AV), which lets you renew a daily spell so you can slam two flaming spheres or stinking clouds a day.
This gnome can take some hits with his decent AC, decent HPs, and decent Healing Surges. He can sit at or near the front line, creating areas of damage behind the enemies front line and then blowing those enemies into the area. He can extend those areas durations sometimes as well. And he compliments the defender and perhaps some strikers by pushing foes around and dumping damage spells on spots they are stuck to.
Sure, it ditches stealth (you can take it at 8th level if you really want), and ditches the feat that required dex (it was not worth it). But it's focused on a concept, and it's a control-themed concept that will work pretty consistently. I think it would make one bad ass gnome wizard.