There would be other ways to ID'ing files without having to go the route of multiple forks as with classic Mac OS. However, it gets to be a little expensive to scan headers for every file you click on, let alone for files you aren't clicking on. Just look how long it takes Mac OS just to calculate how large each file is when displaying a list view. You're safe for now with HFS+ volumes, but if you want to use UFS you'll have to lose all those ties to classic.

Extensions also help YOU to see instantly what kind of file you have. It isn't some convention that has just been perpetuated for no reason. It's simple and convenient accross multiple platforms. Mac OS has been alienated from the rest of the computing world for far too long. It's still a second-class computing platform (no offence intended), but it's making head roads. Some of the blame has to be put on applications. Even though some apps were released with counterparts for both major OSes, some vendors refused to parallel their features and conventions (hint: ADOBE)

Now if only Steve would let the talent at Apple abandon Aqua and create a real UI. Aqua, though sometimes pretty, lags Windows by at least as many years as the classic OS (in some ways moreso). At their current rate, I'd say they're at least 5 years behind Microsoft in UI and usability. Actually, at their current rate I doubt even with unlimited time that they'd "get it." We'll have to wait and see.

Bruno