The following things I don't like:
- passive AI
- generic units and wrong combat balance
- primitive traits/ancillaries system
- a general lack of variety
That said, it is the best vanilla TW since Rome.

About the AI: don't get me wrong, it's supposed to be a century where diplomatic struggle became much more important, but I haven't seen it. If there was active diplomacy, with some nations forming coalitions and fighting someone else (even if it's only me), I would've been satisfied. Right now, the only nations that fight are those which have a quarrel from the very beginning (Russia/Ottomans, Danemark/Sweden, Poland/Austria, Mughal/Maratha, etc.). It felt like everyone died, since there weren't any alliance messages or the like. No diplomatic action (except sometimes a Nation Destroyed message) for the whole campaign. That was on M/M by the way, I'm not sure if it difficulty changes something here, but I will start an England VH/M campaign later.