First of all, mysqlnd is not a proper extension itself, but a backend for the mysql / mysqli extensions. Anyone that bothers to build PHP 5.3.x knows that mysqlnd replaces the libmysql dependency if the --with-mysql(i)=mysqlnd flag is passed to the configure script. Which brings me to the point that the author understands little of the internals themselves.

Second of all, people should man up, step up from their lazy ass and move on. If the code is so really hard to refactor, maybe that code sucks really hard in the first place. I've seen incredible piles of garbage PHP code just to keep PHP 4 compatibility. It's 20-fu-11. 5 years since PHP 4 is officially dead. Maybe, just maybe, the internals team is not to blame for this stuff. I'm not even mentioning sentences containing the word "security" that seems to be some really scary stuff for some pumpkins still trying to figure out how SQLi works.