The issue with this is that then it messes up my last.fm statistics because it submits exactly what the tag data is, so it'll include the manual seperator in the tag data. Wouldn't be too hard to make MC separate two albums if the [Date] or [Year] file tags contain different years?
Then maybe you should label the albums the same as last.fm does: "Diana Ross" and "Diana Ross (Expanded Edition)" and "Diana Ross" and "Diana Ross (Reissue Version)".
I'll point out that the way you use the date field on a track may not be the way others use it, so that changing the definition of album to include date could mess up what other people are doing. For example, tracks are often released as singles before the album; this happened as a matter of course years ago. If people are using that date, many tracks on an album could have different dates, and thus different years for an album that was released early in the year. There's no one way to satisfy everyone.
Personally I'd be fine with using the year. But I'm a user just like you, so I'm not going to debate how you'd like MC to behave or how hard it is to change it. I'm just telling you how it does behave. If you want your albums separated properly, you'll need to fix your tags.
For your example of the Ross/Diana Ross albums, they actually have different titles...
Actually, no. If you look closely Zybex, there were TWO different sets of albums with duplicated names. Two albums named "Diana Ross" and two named "Ross". Four albums total.
If you absolutely refuse to fix your tags, then you can customize your view to split albums based on year.
Remove [Album] as a category, and add an Expression instead:
Expression: [Album]-[Year]
Expression to display: [Album]
Then (for standard view) you will need to set the thumbnail text at that level to display [Album].
Learn more about customizing views by reading
Marko's excellent tutorial.
This just changes how the information is presented. MC will still consider the tracks part of one album, which affects things like volume leveling and other functions.
So I suggest you just fix your tags.