I agree about gumey, but I disagree regarding Production not being a big problem. The types of yields of the building provides are a bad idea as well. One shouldn't let a civ that can get tons of Production from it's ancient era UB (on top of other bonuses) get so much more of that yield. It's a clear snowball thing - many monopolies always means you've snowballed, conquered, whatever, and this is the civ that benefits from that a lot to begin with. I think it should only be getting a single Golden Age point and the already existing bonus trade route gold for monopoly.
I wouldn't mind taking off the flat gold and replacing it with a 1

/2

scaler, since it would play into Netherland's Tall focus. Ultimately I would prefer to take the scaler off though, because that bonus is already on the Stock exchange.
I fixed the problem. There was no 'AND EXISTS' check on the VPEE compatibility for the Waag's population scaler. I didn't see any other errors in the compatibility, so Enrico's got a sharp eye.
I like the scaler being kept, but does Netherlands really have a tall focus? It's pretty flexible I'd say. Warmongering works better than tall I think because each luxury can provide you with a bonus twice, once for selling, another time for buying it. A tall guy has what with his 4 cities, 2-3 resources? Maybe 4 with good luck. A warmongerer can puppet cities to get a resource they have and trade it or even gift it, proccing the UA. It having two good UUs helps. You get many more luxuries to sell, and there's still probably as many ones to buy or ally city states for. Tall Netherlands usually has a problem of everyone DoWing you the moment they feel you're a good target, and the UA/UI means you're going to become just that. Less cities might mean it's all worth more, but you're way more vulnerable when the UA stops working, and for periods of time it will. Then they also hate you and want probably as much Gold for a luxury as the Gold/Culture proc from your UA is worth. If you declare the war yourself, you can take enough luxuries to have their monopoly and leave them just enough land with resources so they can trade with you as your vassals. Everyone hates you even more, but they might also fear you and start giving you decent deals. They can agree to a demand if you have a stronger army, which is a free UA proc.
I'd say Netherlands should be a warmongering menace to the world, especially considering how good the UUs are for supporting such an endeavour. UI/UA also point you there, in a way.
Anyway I think 1g/2p scaler seems like it'd be fine without the flat 2 gold. Or something else, like making the bonus Merchant it has worth working outside of the capital if you can grow it so much it just works it without problems over obvious targets like Polders/GPTIs/potential pantheon supported tiles), which is not always doable without right religious choices or wonders. It sucks it gets a bonus Merchant when Polder provides much the same yields as one, but better, adds food and there's more of them on average, and the city governor loves working the merchant over a polder in regular cities for some weird reason which actually means Waag requires more management so it isn't a yield net loss.