maybe youre right, but Amoi n821, or JiaYu G3 have 4.1 JB, and will have 4.2 in March-April. Plus many Chinesse phones have good devs, that's becouse we can see many ROMs that have difference with stock ROM. Most chinesse phones have LeWa OS, that have weelky updates, but for Europe it's not good OS, only Chinesse. i think that if any of these devices will have miui support , at least for a short time, then there would be people who would be able to implement support for these models in the future. as happened with the Sony Xperia line.Discrimination you will have when your device manufacturer will not update your phone to the latest android version, instead will release new model with e.g; jelly bean. MIUI has learned that only top smartphone manufacturers will support their phones for a long time. Thus e.q LG was abandoned by MIUI because it never updated android devices and often left users with their old phones. And MIUI is for much faster devices that you have and for most recent android versions. Plus, device will get MIUI if it has high user support and big community. MTK chips are for cheap China phones that don't have much user support and manufacturer support.
You have to ask yourself a question: "will my phone can be supported with MIUI and get weekly updates for a long time?"
Its up to your device manufacturer NOT MIUI. MIUI is based on official stock rom. So get better phones like Samsung, Nexus or HTC.