Noble rebels did it in 1.6 and 1.7 but they changed that without mentioning it in the patch notes.
Taking influence + aristocratic isn't bad, but having sub-20 provinces when you've 1) westernized and 2) finished two idea groups means that you're going to feed up vassals 100ish provinces and suck on the autonomy or gimp your expansion and money for too long. Even if you rush westernize (I managed it before 1520 as Sunda for example) you still won't finish those two groups until much later, because your first group is exploration then, meaning you need 3 groups (and no humanist or religious) to switch. By then you can well over triple the province limit without batting an eye.
And that's what sucks about doing it with the decision, always has. You sacrifice a tremendous amount and rely on luck of the ruler draw to convert to the government type that is less dependent on luck. Forming Tibet has the same issue; to culture drift into that, you have to lose enough provinces to be able to drift. They really went all out in denying non-western players republics in a viable fashion, to the point that despite that I hate monarchies I generally stay them unless I get revolutionary rebels in 1.8, and even with those you need to be lucky enough that they spawn near your capitol and don't die, unless you can accept them these days (I doubt it).
