I hate to say it, but I think the author's objections seem to stem from his lack of understanding of character encoding issues. I don't know Bengali at all and so I will try to refrain from commenting on it, but I do speak and read Japanese fluently and Han Unification is a very, very good thing. Can you imagine the absolute hell you would have to go through trying to determine if place names were the same if they used different code points for identical characters -- just because of geopolitical origins?

Yes, there are some frustrating issues -- it has been historically difficult to set priorities for fonts in X and since Chinese fonts tend to have more glyphs, you often wind up with Chinese glyphs when you wanted Japanese glyphs. But this is not an encoding issue. Localization/Internationalization is really difficult. Making a separate code point for every glyph is not going to change that for the better.