I completely agree. I see people all the time, even regular contributors, posting links to MSDN without the parenthetical version specifier omitted. It often causes confusion, linking to an older version of the documentation. Yes, there is an "Other Versions" link at the top, but a lot of people don't notice that. Especially new programmers, those most likely to be asking the questions and referencing linked docs.
Jon Skeet's "Answering technical questions helpfully" specifically recommends removing this from links:
MSDN and JavaDoc documentation, or the equivalent for other platforms. With MSDN URLs, if they end in something like http://msdn.microsoft.om/foo(VS80).aspx, take the bit in brackets out of the URL (leaving http://msdn.microsoft.om/foo.aspx in this case). That way the link will always be to the most recent version of the documentation, and it doesn't give WMD as many problems either.
I've also seen these parentheses mess up markdown formatting for inline links. As the syntax is something like
[Link Text](http://www.example.com), a closing parenthesis in the middle of the URL can cause the markdown engine to render the link incorrectly.
Sure, it can be fixed by editors, and I fix these links pretty regularly. But it would be much more convenient for everyone if this process could be automated. And it seems to me a pretty simple thing to automate.
I'm not sure what slugster is referring to; I've never seen those links break when the version wasn't included. I never include them in links in my own answers, and I've never had any reports of those links not working as expected.
You do lose the ability to link to a specific version, but that's easily noted in text surrounding the link. I think this is a small price to pay, considering how infrequently people want to link to a specific version of the documentation.