I'm in Steve's camp.
I remember a post back in the arduino.cc forum where an Op was upset because s/he had so much left-over unused flash and the under-utilization suggested to them that they were using too "big" of an AVR for there purposes.
We all laugh now.
But, what if they had a really good argument? Should they port to a tiny_AVR such as the t85? Is such a concern even reasonable when at that time a _328P uC was less expensive in quantity == 1 when compared to the t85?
The above is all rhetorical but just thrown out to get you thinking; for small hobby projects with uC + board prices around $3 USD, do we even care? I do not. At 100+ commercial units, you better believe I would put on my procurement conscious hat.