At the moment they can't due to:"Westernising" should definitely be difficult and exceptional. But with a point of divergence set in 1444, Eastern/Indian/Chinese/Muslim nations should have some way to remain competitive with the west.
1. Tech cost penalty
2. Monarch point generation penalty
3. Worse starting tech
4. Worse troops almost all game long
5. Worse national ideas
6. Worse bonuses and events (since Europe is so well fleshed out compared to the rest of the world, it has a tons of events which grant extra monarch points or reduce tech costs)
7. Worse religions (somewhat better since 1.5 though)
Especially the monarch point part is awful. If you expand at a decent rate you just cannot keep up in tech and ideas. Maybe, maybe, if you make a lot of sacrifices you can keep up in one direction, usually military, but even so you'll have a maximum of 2 military idea groups (I doubt they'll be full though).
Oh, and of course, there are no lucky nations outside of Europe (I need to check but I'm quite sure about this). I don't understand why Manchu (for example) isn't lucky.