The National Horse Trainer is working the way Hydro and I want it to work. All I can think of is that the text that goes with it must be misleading in some way. I'll see if I can get time to look at the text later today.
It still is national horse breeder... and i don't think it is working properly. It should unlock horse trainer buildings in every city as it promises to do.
So some national resource wonders should produce nationwide results and some don't ? And you claim that this is intentional ?? Even when the horse trainer building clearly states in every city and sevopedia that national horse breeder wonder unlocks it ???
Sorry, so many of your claims and very hasty assumptions have proven to be inaccurate and false that I just don't believe you anymore. Even if you were right, this national resource wonder x produces nationwide results while national resource wonder y doesn't(even when it claims and promises to do so)-system is totally ludicrous in all it's illogicality and falseness.

But even so I know that my skills are limited and I could never carry the mod like DH, T-brd, Sparth, alberts2, Toffer90, and any other member I've failed to mention does. What I can do is make "tweaks" and add balance in some areas just from the sheer fact that I've played this mod since inception. But even elephant memory JosEPh (former co-workers called me that in RL) forgets things from time to time too.
But once things get somewhere i could be useful i will help
. It just says it provides horses in one city. The buildings you are going on about require horses in the vicinity of the city. This NW provides horses in the vicinity of one city, with some effort made to make sure that it can only be built in a city that does not already have horses in the vicinity.