Playing a game as Timurids right now, it feels really weird. I can't speak to overall power as I'm just entering Medieval, and it feels like they don't really pick up and feel particularly unique until Medieval/Renaissance, but I was pushed into going Tradition as I had no nearby neighbors early on. Now I'm facing a Shoshone that has invaded my land with their stupid border blobs (I have 4 cities in very spread out positions since I'm not worried about invasions).
One thing I noticed was it doesn't seem like there is any indication of what you received for free. For example, I took a city state since my military was sitting around unused, but I couldn't immediately figure out if/what buildings I received, there were only notifications for conquering and the +yields to my capital. I dug through my buildings list and found I had gotten a Lighthouse and Walls (neat), but I could see it being a bit annoying later in the game when you have to scroll through a ton of buildings.
I'm not sure how plausible a pop message is, though.