their diplomatic network assured them to fight whoever was their enemy with the most of the world supporting them.
right...remind me who backed the UK against the frigging Boers? Oh right, pretty much nobody. Germany, France,, Austria-Hungary, the US, even completely random countries like Chile and Russia were on the side of two tiny (by comparison) republics. Britain's navy was neither all-powerful (despite the propaganda) nor all-encompassing in 1815/1830. It was only due to French "appeasement" that her navy took until the Second Empire to recover, only due to Britain's meddling in Spain by backing both sides in the Carlist Wars (following on Britain's almost wholesale and deliberate destruction of Spanish infrastructure during the Peninsular War) that Spain's navy was unable to recover. And yet, Spain and France still managed to claim the second and third spots for the most powerful navies in Europe. Followed by the Dutch and the Danish/Russians, depending on the decade.
No reason that with Belgium, the Dutch couldn't surge to top three.
It's not sure at all Germany would form as OTL, because Bismarck wouldn't have been able to promise Napoleon III parts of Belgium and Luxemburg, thus France could have sided with Austria in the Austro-Prussian War.
there's a lot of ways Germany can form that doesn't involve Bismarck. Schwarzenberg was there nearly a decade earlier, and it was only being hamstrung by the fact that the Russian emperor had troops in Hungary that forced him to accept the Olmütz Punctuation. The Four Kings' Alliance (Bavaria, Hannover, Wurttemberg and Saxony) was a thing in the 1830s and the 1850s (in different formats) in opposing Prussia. Had Metternich not been in power in the 1830s and Schwarzenberg lived in the 1850s, Austria could've easily signed onto those alliances. Instead, she remained "delusional" in her belief that Prussian/Austrian interests were the same (in the 1830s) and both the Olmütz Punctuation and the Erfurt Declaration agreed to a "bi-polar Germany".
If Belgium did not exist I can see the Dutch gaining the Dutch speaking part of Belgium while the Romance speaking part of Belgium may be honestly given to Liechtenstein.
this is a joke right?
I do think that it might be possible that Dutch policymaking would be changed if the Dutch state was intrinsically different from OTL, as a territorially larger state with a much larger population and much more industry.
as others have said, the Dutch would likely
not sell their holdings on the Gold Coast or in India to the British (they might actually attempt to purchase what remained of the Danish Gold Coast and Danish India*). So that could also affect Dutch foreign policy.
*both sold to the British OTL as well
I just thought them trying to rival the Brits in the midst of this British hegemonic century
in 1830 this title was still up for grabs. Until the 1850s/1860s, Britain and the USA were still playing chicken with Latin America. Most British politicians (mostly liberal, but the odd conservative as well) didn't trust the Americans. As far as "industrial complexes", it was after the 1850s that the British and American trade relation reversed. Whereas before, Britain had been the producer and America the purchaser, after the hungry 40's and with the "peace" between Britain and America, America became the seller and Britain the buyer (cotton, wheat, etc etc). If the people who organized that (can't remember the politicians offhand) aren't in power at the time- very possible given that it'd be 20 years after the POD- it can look very different.
And for the Franco-Dutch relationship I completely agree with you, and an alliance with a) Prussia (for territorial defence) and b) the UK (to protect their colonies and their naval and economic interests) would be the best for the Dutch.
and yet, when it came down to it, there were no alliances between the Dutch and the Prussians (neither marital nor otherwise). Willem III married to a half-Russian Württemberger princess, then when he needed to remarry, he didn't choose a Prussian princess. For his sons, the ambition was not a Prussian princess, but a Hannoverian one (or a British, if Queen Sophie had gotten her way).
True. I think France would ally with Austria to counter Prussia, and if Austria is defeated, then the French would Switch to Russia. Like OTL, the UK wouldn't intervene much in continental Europe, even less in a continental war, unless the Netherlands's very existence is threatened (or the risk of a break up of the Europeans balance of power as usual with the Brits, but it wouldn't be a problem ITTL until late).
explain again why Britain would intervene if the Netherlands is threatened? English and Dutch interests had been at odds for nearly two centuries by this point- with only occasional "get along periods" (mostly because Britain took all the most valuable Dutch colonies except Indonesia). Their "sponsoring" of the creation of Belgium was basically a deliberate attempt to undermine the Dutch. Not sure why they would care if the Netherlands' existence is threatened.
You're right, except now Prussia and the UK are also allied with the Netherlands. However the Austro-Russian relations could get more tensed (it depends if the Crimean War happens, if not then they could stay allies for quite some years). To sum up, a big continental war over the German Unification is possible for the 1860-1870's. As to guess what side would win the War, it's near 50/50 to me, Prussia and the Netherlands would be really outnumbered by France, Russia and Austria. Yet the Prussian army was the better in Europe at the time, so no clear advantage for anyone IMO.
Anglo-Russian relations were actually pretty darn tense through the 1830s and 1840s IIRC. If anything this alliance- not sure why, both George IV and WIlliam IV were anti-Prussian in general- will make things even worse.
I wonder if the butterflies might have ramifications elsewhere. Like, does Denmark end up differently?
only if Fred VII marries a wife who can actually produce an heir
Maybe, in the future, France could annex Wallonia.
Willem I actually signed an agreement where he basically said he'd allow Henri de Chambord (if restored) to keep parts of Belgium/Luxembourg- cue Franco-Dutch alliance. Not sure why the Dutch will automatically side with Britain in these scenarios. That they did OTL is one thing, but this is a whole different scenario