My tablet did get progressively worse when the problem first arose. Since my initial posting the dead zone hasnt gotten any larger however it may have become even less responsive. Although i can still get the tablet to register clicks in that region the pressure required seems to have increased, but I can't say for sure.

As 9a60r pointed out, I also am able to draw a line starting outside the dead zone and have it continue into this area but, thanks to Maemopad+'s pressure sensitivity, i can see that the line's thickness does decrease when the line enters this area and subsequently increases back upon exiting.
Anyways its nice to know that others have experienced this. I still havent resolved to send my tablet into nokia.
I'll try reflashing one of these days.