Unicode 3.1.1 has been released. The cross mapping tables for east asian encodings and character sets (http://www.unicode.org/Public/MAPPINGS/EASTASIA/) became obsolete. These tables are now moved to http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/ and there you can read a comment by Asmus Freytag on the obsoleteness and problems which I pointed by this document. Thus, the problems I stated (in the following chapters) which are based on the tables are also now obsolete.
For example, "EUC-JP round-trip compatibility" problem doesn't exist now because JIS0208 conversion table is now obsolete. "Conversion tables differ between venders" problem also doesn't exist. "Width problems" also.
However, this means much larger problems. Now we don't have any authorized mapping tables for east asian encodings. It is absolutely free for venders to implement arbitrary tables. This will make the situation much worse. At least, The various encoding tables (now moved to http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/) will never be unified.
Unicode is a standard. Not supplying an authorized unified reference mapping table seems to show that Unicode abandons the responsibility as a standard. The comment by Asmus Freytag sais that EastAsianWidth problems I pointed are "mapping file issue" and "mapping file error". Then, why not supplying a correct mapping file?
In pre-Unicode-3.1.1 world, we had a problem on various mapping tables where a dozen of code points were problematic. Now, we have lost authorized encoding tables and all code points (except for UniHan characters) are problematic.