If memory serves me rightly Tegra3 is one of those weird arrangements that either downclocks or has a fifth processor core running slower than normal. Irrespective of how they do it, NVidia are making great claims for T3 - specifically that in normal use the battery life is much improved on the T2 dual-cores. So you get the potential for more processor power and longer battery life - win/win as far as I can tell!
Not being an HTC owner, I'll bow to your greater knowledge - thanks.
First part - no, disagree. I don't think anyone's expecting updates ad infinitum. On the other hand, we have folks like SE who launch a phone and then six months down the line terminate it. I would politely suggest that - where the hardware permits - OS support for 2-3 years would be reasonable.
Second part - translation: get yourself on xda-devs. I don't agree with this for two reasons, (despite until recently running an xda-devs provided ROM myself). Firstly, you can't expect Joe Public to go through all that nausea of rooting, rebooting and reflashing - if that's what it takes then the Appleistas are going to laugh at us - with good reason. Secondly, even if you follow that route, then there's the problem of getting support - xda-devs disallow posting to the ROM threads until you reach a certain post value - so are we seriously suggesting that folks post rubbish to other areas, just so they can ask questions? Again, not sensible in my opinion.
Good thing is that this probably won't be necessary, since pretty much all the phone makers appear to have realised that there's an expectation that the consumers shiny new device will receive updates for a reasonable period of time. Devices that don't follow this get widespread bad press, and those in the know will unfailingly avoid them, and recommend that others avoid them.