Instead of directly reducing science generation for going wide etc, you could instead give advanced science wider negatives (or indeed reduce science generation and provide other negatives). So, for example, perhaps as you unlock certain Techs, you're Cities’ requirement for Amenities increases, representing your Citizens demanding a higher standard of living. Or perhaps Cities start requiring power, so you actually have to get power infrastructure in place otherwise all your Citizens get cross and start rebelling. Or maybe your Cities just generate more pollution even without powerplants etc. At the moment, the only "downside" to high Science is (1) increase district costs, which is easily offset via chopping, and (2) your tech maybe outstripping your policy cards. Neither is really a significant downside, so you're pretty much always rewarded just pumping pumping and pumping Science. The advantage of these wider downsides is that players could still rush science if they really wanted to without building up other infrastructure to support it. But if they did that, they’d have to find other ways to mitigate the consequences and or adapt to living with these negatives (the same way warmongers have to cope with war weariness).