It is cases like this I wish Android was more....Apple like.
Why can't we have the most current Pure Google phone on every network, is it really that complicated?
It is that complicated honestly.
Apple controls the hardware. Google doesn't...that's why the HAL has to change (along with many other layers) to support the different processors, wifi, bluetooth, 4G, 3G radios, etc, etc. There is 1 and only 1 hardware spec for all iPhone 3GS models. Apple can write iOS4,5,6,7...etc all to support backwards compatibility for as long as it makes sense to...they write the OS & spec the hardware.
Its like trying to put a different engine into your car...you might have the space under the hood for it to fit, but it has to be modified in many ways in order for it to go in, connect to the transmission, run the A/C, Heat, Radio, Cruise Control, etc and then actually move the car down the road safely....ICS is no different.
Its not just running some setup.exe and it all starts working. Its extremely complicated.
I also do not want the Apple model...but if you truly want to be relatively 'safe'...the Nexus line is the only option for you. The Google model allows for things like integrated kickstands, different screen resolutions & sizes or 2 folding screens for that matter.
It is a little frustrating that the manufacturers put their own layer on top of the OS...I agree with you there.