MC's unbelievable complicated and un-friendly UI
Why? I don't find it like that. I would like to see some argumentation here. What are you comparing to and what are the main differences? MC is extensive and it has many possibilities. There must be an interface for that all. Though I have used first MJ and then MC for years, maybe I have learned slowly to use it. But when I first installed MJ I was instantly positively impressed about the software. That time I was using Winamp 2.xx with EZ-Playlist plugin for file organization and tagging. I had then tried and dropped e.g. MMJB and Real One.
Since then I have tried Winamp 5, WMP9, iTunes and Foobar2000. Foobar2000 has some excellent technical capabilities, but I don't think anybody can say that its user interface is friendly or easy to use.
Any of them doesn’t come even close to MC if you are going to maintain a large media library. Besides music MC can also maintain video and image collections.
In fact, MC10 now only shows the filename (truncated to artist-title) in the "Name" field. No other ID3vX information is shown. I remove all ID3v1 from the files, but the ID3v2 info is in tact and visible with other programs.
I don't know what happened in your case (you should give specific information about how that information disappeared), but here is how MC basically works:
When an MP3 file with ID3v1 and/or v2 tags is imported MC reads the information and fills the relative fields in the MC library. If you change the information in the library fields MC writes the changes to the file tags. (Tag writing can also be disabled, as you know because you have tried every setting.)
MC does not usually read the tags after importing the files to the library. The assumption is that MC maintains the tags (=writes changes). You can force tag reading by using "Update Library (from tags)" command.