Well to be honest, more pixels are good, but apple went overboard. the 5800 i had looked better than my ipod touch, and the n900 better still. the n900 balances pixel count, clarity and text size/ui perfectly imo.
optimum resolution for a 3.5" screen is 640 x 320.
optimum resolution for a 4.1" screen is 800 x 480
optimum resolution for a 4.5" screen is 960 x 640
I sport higher resolutions on smaller screens so long as i can set the display resolution like on a CRT with no degraded image.
Just like loud music damages your hearing, staring at high detail a few inches from you face for a prolonged time has a negative impact on your eyes.
Probably because its just a copy of the N8 OS (Symbian^3).
Also, the video reveals the device to be RM626, that's not a Maemo/MeeGo device code (RX*). Considering Nokia doesn't even have an OMAP3 Symbian device, I find it very unlikely to be the N9.