What if the academy got a set number of + a small % bonus. That would make it more valuable over time but only slightly better early on. For example. With two cities and the NC up and running, your normally at ~30 give or take a few. What if you had then a 5% bonus? That would give you 1.5 extra, which would go up slowly as your science increased. At 100, you'd be getting 5 extra; at 200, 10; and etc. Settle a couple, and it could really add up over time but not enough to be OP.