I agree that the feature is weak and will not really be used, or, when used, will not change the game in any significant way.
The reward is too low for the invested effort, it's just more % over more monarch points spend.
Imho it should be changed to making a list of current innovative countries, with the top 10 (or 5, needs to be balanced) most innovative getting some strong bonus. Maybe getting a very high prestige bonus, getting an attration of immigrants, giving unique events (that can raise development, reduce tech cost, completly remove ahead of time penalties for a while, giving unique especial advisors, stuff like that) maybe make a list of inventions into the game that can be created my innovative countries (like some of the events that trigger changes in prices in trade goods), and giving the inventor a permament extra bonus (like finding the 7 cities in the new world).
Right now it's just another modifier, not a lot of flavor, no reason to worry much about it or any real necessity to keep up with it.. (not having it doesn't give any negative modifier)