[Cap Ologist]

Quick question about overall strategy. When I first started playing, I would always annex and build a big blob of an empire. In my current game, I've only annexed 4 provinces (playing as Switzerland to get to a port, took the gold provinces from Aquileia to the east around Venice). I have probably around 15 vassals. My research is out of this world, I have a huge lead in land, govt. and trade.

Is there a point where it makes more sense to have the blob but have slower research, or is having quicker research and allies who are forced to fight for you better? I'd like to annex Tuscany and Pisa which control the Italian universities and are both currently vassals of mine. If I annexed all my vassals, I'd have greater income to spend on research, but I'm not sure how to determine if it would offset the increased costs?

Any thoughts? Thanks!