I don't see why it would be disastrous, since Jack's no slouch defensively, but it seems likely to invite thuggery from the usual suspects.
Guaranteed midfield starters: Arteta
Midfield options: Diaby, Jack, Cazorla, Ox, Ramsey
Guaranteed wide forward starters: Podolski
Wide forward options: Ox, Theo, Gervinho, Cazorla, Jack
Way I see it the lineup where we have Diaby and Jack or Cazorla in midfield, and Podolski plus Jack or Cazorla at wide forward is quite balanced, and gives us the option of pulling a high impact substitute off the bench.
If you select Cazorla and Jack in midfield, you have a very diminutive lineup, and your best remaining starting option at RF is probably Ox, who is still a less polished option than either.
In practice, Wenger's going to select the midfield we saw against Liverpool for big matches until one of them breaks down, but that's quite likely to happen sooner or later. Wilshere should have several outings as a sub before he starts again ...