Even though that is sound logic that's still incorrect. WCDMA really is just another word for UMTS which is much similar to that of GSM than that of EvDO 3G found on Sprint and VZW's 3G CDMA networks. You really need both frequencies (1700 and 2100) on the phone supported because without it...
The only reason why 3G works on your Droid X is because both Cricket and Verizon both use the same network technology, CDMA. It's not to difficult to convert a vzw to a lesser carrier, however it's not like you can get an AT&T iPhone to work on Sprint or VZW, it simply that they are two...
All of the MIUI Ports (unofficial builds) need a copy of cyanogenmod in order port over necessary libraries and other dependencies.
If it gets that, and someone is feeling intrepid enough, then maybe you could see a MIUI port.
I hope this helps,
Or just remove it with root explorer, just call me old fashioned :P If you're going to remove it from the rom, be sure to remove it from the deodex Chinese rom AND the language pack if your phone uses that format. If everything is packaged into one file then just delete just the one.
MIUI isn't just a rom, it's a suite of apps, including miliao (MiTalk). If you have a working knowledge of adb you can do the following commands to remove MiTalk.
Hope this helps
I feel that he think's it's outdated because it's no longer called Miren browser, simply MIUI browser. It's included with the past 2 weeks releases by default. Nothing should have been gotten from the Market.