one thing I'd really like to see is an option to fit a larger battery; Nokia have done this in the past with various mobile phones, there's a 3rd party battery for the 810 which does this.

if there's to be an N900W (wimax), I'd like the wimax module to be removable and swappable with a 3G module or LTE or something.. even if it required a screwdriver to do it.

I think it's unfair to ***** about Nokia. Compare the 800 with the 770; people complained the 770 didn't have enough memory (fixed), didn't have USB host (sorta fixed), had only one memory card slot (doubled, and SDHC too), mono speaker (fixed). The n800 had other bonuses - fm radio, camera (for basic video calling admittedly). In fact the only consistent complaint was that the n800 didn't have the heavy plastic half-case of the 770.
Then people wanted a keyboard and gps, so along came the 810. Then they wanted wimax.
OK, sure, I want the moon on a stick:http://www.chiark.greenend.org.uk/~s...-on-stick.jpeg
But product lifecycles, the volume of sales (minuscule compared to even the highest-end mobile phones) means unless you can stump up 10's of $M, we're never going to get the perfect device!