One thing that strikes me as utterly bad with how scientists and science generation work this age is two things:

1. The scientist generation is way too low.
Even when running high amount of labs, there is hardly any progress at all.
Also low amount of scientists also works against versatility, and the feeling of having a great province late game.
If the rate stays put, then another way to help would be to double sci rate on base, labs and rev, but half book generation(and ofc the max books for level up).
that way its easier to focus more on what you like, and spread things more easily out.

2. That a scientists that learns all the traits and knowledge from one field, starts a new field of research, and then suddenly doesn't know anything about what he just spent years learning - logic's pls!
My proposal here would be a multiclass system - like some MMO's etc. you gain level in the field you go to. so you could if you wanted master all 3 research fields.
You could make a grace period(the scientist needs to find old notes and books he have done before). e.g. 12 hour grace period, 3-6 hours with no books, 6 hours with reduced books generated, then back to professor as he was before.

this would mean alot to those that want to work for their science, optimize everything and give alot more versatility for the lords of the provinces.

make it happen! :-D

/Kilim