First off all, I have little to none modding knowledge on this game, yet
So any suggestions I make, which are not within moddability... well
Ow, and second... graphics part, awesome!
And another while typing, some stuff is repeated from earlier. Unconsciously, so I stand with (some of) my points
About the leader/UA. I take your word for it that you didn't mix and match. But you still got an empty slot
Willem was a man of (foreign) relations, and "my word is my bond". He was also a liberator of occupied cities.
-This could mean he gets bonuses from contacts with other civs. Like a +1 gold per era per civ. Meaning that in the medieval era (3) and he knows France, Ottomans, Germans, and America he gains 4x3 gold=12 gold per turn. This is not much, but can really add up. The numbers can also be tweaked ofcourse.
-Another idea is, that he either doesn't cause an occupied state. Or he gets a hefty bonus for building courthouses.
I would stick with 2 unique's, so either a Watergeus and/or Flagship and/or Dike. I prefer leaving out the Flagship, but that's personal.
So the Watergeus is now:
100
, 10
, 3
Bonus vs. Mounted.
Right?
So they get +1 move. Well, they were mainly "Robin Hoods of the Netherlands", and I personally would love it if they get bonusses from fighting in rivers/marsh tiles, hence the "water"-geus. Either that, or no movement penalties from those tiles.
I just remembered there is a promotion... Amphibious
The VOC was sailing to another end of the world, and trading. Meaning armed, a very big carrying capacity and fast. You got the fast part
Maybe add the promotion of "Targeting", a naval promotion. And reduce the
cost, to equal cost. A visibility/sight promotion -scouting the new world- could also fit. Or "can carry cargo" promotion.
About the Dike, what I mean is that instead of adding 1 great engineer point to the pool, it should have a great engineer slot. It's less powerfull, but you need someone to keep a
finger in the Dike before it gets breached.
Btw what is the prerequisite tech? It looks like a courthouse, but with extra's.
And, I wouldn't recommend it needing a wall. Building requirements are demanding as is, especially for a defensive building. Maybe replace it for the wall?
At this point in time, I have no idea for the polder. It's something dutch, so I would drop it, I think.
Again, I have no idea if this is possible, but maybe you could ask around.
ASE: What did it do? It boosted commerce!
Why not just (and only) a basic GPT? It's not that exciting, but if it nets you +10 gold per turn (what tech unlocks it? Compass?), it gets very nice with some +%. I would build that! Merchant ok, culture ok,
depending on tech, at least +50, maybe 100.
Also, 30% in game info, and 20% in stats, where happiness etc is. That no one noticed that before!
Delta works: Still love the picture!
What it does is protecting from the sea. So, if this is moddable, you get a "wall" around all water squares within your borders. Effect, like the great wall, but aqautic. Secondary is that not all water tiles are blocked by naval units, only the one they are on.
Dolmen: So they are burial mounds eh. Hmmz, what could that add in CiV terms.
Triggers a 5 turn golden age, +2 happiness (+1 culture, +1 engineer)?
thx 
