As an ardent Dutchophile, being a Dutch and German American and because it is probably my favorite European country (out of the 20+ I've visited), perhaps because I've spent so much time there and studied there, I really don't like the approach to WHS.
These failed "Benevolence Colonies," one of which is actually a labour camp, are really interesting and I would certainly go to the event on Feb 13, but these are more local history sites. It seems like the Dutch, and to a certain extent other countries, are not nominating sites of OUV but sites that are interesting in a local and regional context and could use a tourism boost. Certainly Drenthe could use some more visitors - it's a beautiful area and quite interesting. I feel the same way about the Mining Basin of the Nord-Pas-de-Calais in France.
Understandably, 'old towns' seem to be out of favor, but I just don't think the most significant, historically significant, representations of human genius, and places of outstanding universal value are represented by the current T-List (non-colonial possessions). The Netherlands possibly has the most important Enlightenment cultural heritage and it has one of the most interesting (political) capitals and wonderful and influential architecture (especially influential in North America + England around the "Glorious Revolution" and thus in the UK). I'd like to see more Enlightenment sites nominated.
How about the Portuguese Synagogue, which reflects an entire cultural opening of trade with Iberia as well as having connections to Spinoza? It's one of the most beautiful synagogues in the world, as well.
Binnenhof/Ridderzaal + Lange Voorhout (Kloosterkerk, Hotel des Indes, the residence of Johan de Witt - one of the most beautiful streets there is) + Mauritshuis is an amazing ensemble and while the Binnenhof isn't as "grand" as many capital complexes, that's because it's more preserved.
Delft with its Oude and Nieuw Kerks, which house the royal family and Vermeer, as well as the Prinsenhof where William of Orange was shot and killed - representing a link between the beginnings of the dynasty and successful revolution up to the Stadtholders and Kings.
I know it's somewhat in the vein of the "old town," but how about a serial site of the Grote Markts - Gouda (St. Janskerk & Stadthuis alone make this a gem), Alkmaar, Bergen op Zoom, Breda, Haarlem, and others. I would add Leiden, Utrecht, Dordrecht, even Amersfoort - they are incredibly preserved cities, but Leiden should file a separate listing for its extremely important university (1575) that was a hotbed of the arguments between the radical Enlightenment and the conservative Enlightenment. Furthermore, the architectural landmarks (Marekerk, in particular) represent the Dutch approach to the Baroque.
Another Enlightenment idea could be sites related to Grotius, or just a serial set of sites related to the Dutch Enlightenment in general. Delft, Slot Lovestein (part of the Nieuwe Holland Waterlinie also), and Leiden University. Could have a set of sites attached to Grotius, Descartes (Leiden, Amsterdam), Spinoza (Amsterdam, the Hague [Nieuwe Kerk, the preserved home of Spinoza). Erasmus also was schooled in s-Hertogenbosch, but I don't think there's any remnants of the school. Teyler's Museum (perhaps more credible in a serial nom) in Haarlem and the Eisinga Planetarium in Friesland could also be associated.
I'm not sure there's enough "immovable cultural heritage sites" to do a serial nomination for Golden Age painters - but Rembrandthuis & Westerkerk, where Rembrandt is buried (Amsterdam), Vermeer's possible grave in Oude Kerk (Delft), Haarlem (Hals museum, Painters guild, van Heemskerck), the Mauritshuis & the Prins Willem V Museum (incredible little museum across from the Mauritshuis), could all be possible listings. I'm sure I could come up with some more ideas, but I'm just shooting from the hip and I wish that I'd see some more nominations like this rather than more "Man and Water," or societies of benevolence, which are more like National Landmarks rather than UNESCO WHS.