Ability to order list view by time discovered in run (so you can see what the new networks are)
Already on TODO
Make tab buttons larger and put on bottom at least in landscape mode (to ease use in car, they are small and right next to drag down notification bar)
I specifically make them smaller to save real estate

Buttons at bottom on landscape mode would be nice, I think I remember reading it's very hard to do in a backwards compatible way though. I'll put on list.
Ability to filter list view by new networks only
Added to TODO.
In dashboard mode, make the network counts much larger for reading at a glance. Side by side large numbers in boxes would be great as the text justification doesn't line up right now and makes you read into the middle of the block when driving.
Network counts are already larger, that's part of the reason the dashboard exists. I'll left-justify and make them larger in next release.
Ability to turn scan off so you can be on local wifi while reviewing map/stats/etc.
Already on TODO.
Smaller upload button or confirmation dialog to prevent inadvertent uploads (I get a lot of these just handling the phone or even from sitting in my pocket)
Can turn the screen off in your pocket. A confirm dialog might be nice though, added to TODO.
At walking speed, default map zoom level to be in tighter, it's hard to see city streets when pocketstumbling on foot and resets zoom level frequently by itself
Zoom will be remembered in next release.
Indicate new networks since last upload since run counts gets reset on crash
Added to TODO.
Ability to manually define run start/stop points and batch uploads to wigle by defined run
I doubt we'll get into changelists. Upload everything!

Live updating map showing existing points in wigle as well as your new points
On the TODO, and something I'd really like, is to have it draw everything in your db on the map, pry with overlay tiles it keeps updated. That's a significant undertaking though.