It's not that it would look weird per say, it just wouldn't look as good as it could (plus who doesn't like having a wider stance in the back?). Do you want your wheels flush with the fender? If so, you need to go wider.

Here are different 9.5 wheels and offsets. Notice how sunk they are.



Here is 9.5 front +22 and 10.5 rear +22. As you can see it sits more flush and you could even go wider if you dare (which might require rolling fenders depending on how far you go).



Read through various wheel threads and figure out what suits you best.

 

Ah, cool, thanks a lot! Very informative post. It definitely looks much better at 9.5/10.5