I prefer wireless too, - if it works and doesn't have issues with interference. Wires are a pain and can sometimes get snagged and broken.
A backlight that will actually make the display readable from a normal riding position would be good, otherwise you might as well skip it. I've had a couple of computers with backlights that were pretty much useless.
As far as metrics go, temperature is nice but not a must have. I can check it in the house or at work before I leave to decide on clothing. It's not going to change that much during my commute. It might be handier on longer weekend rides, but again it's not really necessary. What would be cool is if it stored the temp info along with any data from the ride it keeps. I have a Polar HR monitor/computer that keeps your heart rate metrics along with ride metrics for the last 14 rides. Adding in temp would be useful and so would altitude changes.
A configurable display would be good too so I can have time and speed if I want or speed and cadence.
To me the only thing that I would consider a "commuter" feature is a backlight since most of my night riding is while commuting.