First of all, I said that it's his rom and he can do with it whatever he wants. Second: Ivan's rom fully supports LTE (4G). Third: don't be a dickhead.The problem with this forum is all novices and noobs are commenting without thinking. It is not the dev's decision to not include LTE. There may be other factors like availability of sources. Even Ivan's AOSP doesn't support LTE.
We are indeed getting custom roms for MI3 which is a blessing. People should rather just keep their mouth shut and enjoy the ROMs.
If you don't like it, you are welcome to leave the forum and not come back. Also discussion should involve only CM12.1 bugs and specifics.
I fully support what linuxxxx is doing here and I believe that in the future he will embed a full support for mi4's LTE. And while you mentioned bugs, that IS a bug. If your phone has LTE bands you can't use, mms is not working,... we write about that because we all want this rom to be even better.