It's been two days since MT 2.661 was released and I haven't heard any word on whether another upgrade will be released to address issues and complaints from MT users. Looking at changes in 2.66 and 2.661, I decided to downgrade my MT installation back to 2.65 for the following reasons:
1. Unwilling to give up MT-Blacklist in order to able to use ThrottleSeconds parameter in mt.cfg
MT-Blacklist 1.62 prevents the ThrottleSeconds parameter from working at all. If I have to choose one over the other, I'd rather have MT-Blacklist. I have yet to be hammered with dozens or hundreds of comments, which ThrottleSeconds is supposed to help protect against. MT-Blacklist provides protection from and easy removal of comment spam, no matter how many or few there are.
2. MTCommentAuthorLink redirection
I don't see anything to like about this. MT 2.6 appended the destination URL to the end of the redirect link, but this opened a security hole where malicious users could use MT as a relay to visit any URL. MT 2.661 fixed this by appending the comment ID instead, and letting MT look up the URL in the comment database. The new code in 2.661 now causes an error to be thrown on the comment preview page, because comments don't have a comment ID before they are posted.
A side-effect of the 2.661 redirect links is that you can no longer tell what the destination URL is (by hovering the mouse over such a link) without clicking on the link (and hoping for the best) or looking up the link in the comments database. This alone was enough for me to be against the whole idea of redirects (not that I was ever comfortable with them in the first place).
3. Improved e-mail address validation of mt-send-entry.cgi.
I don't use mt-send-entry.cgi, so I don't see any of the benefits from improving its code.
Since I can't use the ThrottleSeconds parameter, do not want redirected MTCommentAuthorLink URLs, and do not use mt-send-entry.cgi, not only do I receive zero benefit from upgrading to 2.6 or 2.661, I get a couple of problems that I didn't have before and do not want. Downgrading to back to MT 2.65 seemed to be the only logical choice.