gribble
Explorer
It's not exactly exhaustive playtesting, but I played a 4th level (covenant of Wrath) Invoker alongside a Wizard using the preview material for a couple of sessions.Only true playtesting will of course tell us the real answer, but after reading the classes, my gut says they are quite comparable.
My observations:
1) The Invoker seemed to have a lot more "rider" effects on his attacks.
2) The raw damage output of the Invoker was noticeably higher.
3) Most of the Invokers attacks only targeted enemies, and consequently he was usually able to hit more opponents with his burst/blast attacks than the Wizard (and a few of his powers actually had beneficial riders when allies were in the AoE).
It's possible luck and/or optimisation played a part but in my opinion the Invoker was noticeably better.