A risk/benefit analysis
"The history leak is the result of [...] technology that causes a browser to display links that have been visited in a different color than addresses that have not been visited."
Shit. It would be disastrous if that ever broke.
"It also allows webmasters to customize content and user interfaces on their sites based on the links individual users regularly visit."
You mean, it lets them violate your privacy? Er, yes, that's rather the point.
"Microsoft has so far [only warned] that browser fixes could break websites."
For the reasons given above, I'm inclined to think that this is a load of cobblers. Is there something I've missed? As far as I can see, not only is this an easy fix but it has actually been fixed (through private browsing) in several browsers with no observable ill effects whatsoever.