Ok although this isn't a New Development (since it hasn't been developed yet obviously)...it should definately be one...
If you just have a GPS (no smartphone/iPhone) but want to GeoCache to a spot where you forgot to download some caches, it should instantly pop-up. Like every cache not just like the GeoMate Jr. or whatever that shows you like 7 out of 10 caches...every single one.
No more downloading at all for GeoCaching, just simply have Garmin have a system on GPSrs where you can freely upload caches using internet, and even log your visit look at the clue if you need, etc. That would make all those caches I missed from not downloading or looking on the computer for caches in the area I was heading - count.