2x Wizards + monk/wd + barb is one of the things I will try soon and I think they will be more efficient for speed runs. The problem with pushing high GR is that without that 3rd support, u will die. Sure u will have more party damage, but those wizards will get destroyed fast. U need the monk and the barb cause they provide insane DR. U may be ok for 70-80, but once u go higher, without the CC and DR from the WD, u will start dying left and right. Not to mention the lack of pickup radius will force u to move around to get those globes which will screw your wizards positioning unless u use keymaps just to move 1 char to pick up globes.

Instead u just build a glass canon wizard with a ton of IAS and area damage, u keep him alive, u feed him all the globes u can spawn and u pull all the mobs u can to a single tight corner for him to destroy them.

Check my spec for flashfire in the other post Gearing wizards is pretty simple with it.