Copy and paste of HTML is such a mess (even today in 2013).
I just converted a couple (converted from Word doc) TM articles from HTML into WikiText and it is shocking the difference in the amount of code (and complexity)
Example #1: Bug Database Definitions
Here is what the article looks like:
And here is the ‘Html to Wiki’ Commit
Example #2: Where to Post TeamMentor Issues/Comments
And here is the ‘Html to Wiki’ Commit
In this 2nd case, ironically the WikiText version looks better (look at the difference with the screenshot below with the above) because of the lack of HTML formatting mess: