jeff_rigby - I agree with your sentiment, although it does seem to be a bit of a random rant...
but I note there is nothing RISC about "i386" architecture, and the working definitions of RISC/CISC are somewhat meaningless these days anyway. The only RISC i386 Intel chip was the Pentium Pro where Intel slapped a hardware virutalisation engine on top of a RISC processor to make it code compatible with i386, then realised their mistake in that it was insanely expensive and kludged down the speed benefits of RISC so much that they never went back to that method. By that stage the ideals of 1 instruction per cycle were starting to be achieved by technologies such as superpipelining, branch prediction, out of order execution, multipath execution pipelines, and as you say, caches... shame really!
But I'm not sure that it is fair to say that the developers have chosen the "common denominator" - the ideals of open source projects are that they make the code hardware independant, as Linux base is already. The only problem here is that the people that have done the REALLY heavy lifting for LinuxMCE (Plutohome and Paul) have had reasons of either focusing on their own product or personal bandwidth to deal with that have slowed the process of the actual source code tree being made available. As soon as it is available, like any other open source product you can compile it for anything you please! And from monitoring the developers forum, it sounds like they are getting themselves organised to achieve this....