I dont know how and if it could work, but it would be nice if all specialists would get +1 of their base yields with a university or madrasa instead of science per pop.

Many Library and Shrines should give a bonus to improvements (bonus and/or luxury). This would even them out better and make those locations even better.

Also, the shrines do even more favoritism with this - only woods (and in places with many wood tiles they get incredibly strong), and those who dont have any are basically locked out of religion, likely for the entire game; which can be hurtful for civs such as mali. I believe that this was the reason they had to do it with a set base yield - to prevent some few players with a good spawning bias to have a major monopol on something like science, culture or faith.

I think the level 2 buildings are fantastic.
The level 3 buildings are great too, if not a bit strong maybe, but then again, they might get worth their cost now...
The level 1 buildings i almost all see as... something. The market certainly saw some kind of buff on any map with enough ressources, and even with scarse ressources, there would still be one or two luxuries somewhere, getting it back to it's normal value. But they easily have the ability to be better than usual for everyone, as every player should spawn close to at least one luxury.
But the library, and worse, the amphitheater - not everyone spawns close to woods or rainforests or gepthermal fissues, nor can everyone build pastures early on due to lack of ressources. This leaves the few who have a major advantage in their spawns - e.g. kongo in the middle of rainforest - with a major advantage throughout the entire game, as from the early game it just starts snowballing.

What tweaks? What does this mod do?

details?