Really appreciate your careful observation.
I was aware of this, and it was a design tradeoff that I was willing to take (like this controversy "low-lighting" thing).
The big dilemma is always "how to pack a lot of information into a limited space without looking cluttered". I also tried 980px but that extra 100px does make a big difference (plus considering the "flow" of the text). Therefore I gave up the relatively smaller market of netbooks/11-inches MBAs and go with 1280px screens.
Thanks,
Ivan