I care about the ROTW because that "rest of the world" is a quite large majority of the world. Also, I like to turn the tables on real history. Britain conquered India, so I'll do the reverse. Austria stayed HREmperor pretty much the whole time, so I'll get them off the throne as soon as possible (bonus points for completely wiping out house von Habsburg). Prussia rose to power, so I'll smother it in the crib and establish Hansaeatic dominance. Steppe nomads gradually fell by the wayside and got conquered, so I'll choose one and conquer the conquerors. Poland got partitioned, so I'll take them and partition Russia, Prussia, Sweden, and basically everyone else.
At release, the second largest city in the world (Vijayanagara) was a base tax 2 wasteland. In 1.8, it got buffed to a staggering base tax of, wait for it... 5. It's not even the richest province in its country, despite the fact that it should be on par with the largest cities of China and Europe (and I'm really not sure why they don't just buff it to 10 or 15 - I've set it to 15 and the extra tax and manpower doesn't lead to Vijayanagar ROFLstomping everyone else). I know that it got sacked and destroyed, but that's the kind of thing DHEs are for.
In the current release, same-continent colonization was nerfed. Unless you are or ever have been a colonial nation, in which case, you get to ignore this nerf. Why? Because otherwise, Europeans might not feel sufficiently compelled to colonize the Americas, while anyone playing the natives has to comfort themselves with how many more provinces they can have (and only get half out of). There could be an internally consistent system here (I've proposed one or two) that would put everyone on equal footing while still nerfing same-continent colonization for the places where it's most "problematic", or a simpler rule like "tariffs give twice as much to their overlord as they take from the CN" (effectively nullifying the LA penalty for the overlord while not giving magic powers to CNs). Anything that wouldn't make the situation a giant "screw you" to well-played Native Americans, who should be able to, through reforming and westernizing, close the gap with the colonizers. I'm particularly steamed about this because it means that the natives and the colonizers (even if the colonizers are natives from the other American continent) have fundamentally different potential. No matter how well played a Native American nation/tribe is, it will never be equal to a colonial nation that occupies the same land.
Tech penalties are fine. Europe caught up and pulled ahead in this period, and I can deal with that. That Europe gets slightly better late-game units is also something I can deal with, as is the fact that Europe gets more flavor. However, certain things (eg. the quadruple whammy of worse ROTW units, worse ROTW tech growth, and getting those worse units at later techs, and reduced MP gains that the early versions of the game had, the constant horde nerfs (the first few (like must reform to westernize) were okay, but "must reform to become Persia or Mughals" and "no foreign core recruitment" are going too far) and magic colonial nation super administration powers in the current version) are just going too far. Different nations can start at different levels, but even nations that failed (eg. Byzantium, Vijayanagar, Ming, Native American tribes and nations, steppe hordes, etc.) should have the potential to match or surpass those who succeeded (eg. France, Great Britain, and Russia).
And the game is called Europa Universalis because it's named after a board game of the same name.