What scale does one use to measure Dutchness? William’s grandparents were Dutch, German, English, and French. He certainly spoke English as well as speaking Dutch. His wife was English and so was his mother, but his paternal lineage was that of William the Silent who led the beginning of the Dutch revolt against Spain in the previous century. His history and position were tied to the Dutch Republic, where he lived most of his life and fought for his political inheritance as Stadtholder. He cared most for Dutch territorial interests and preferred the company of Dutch generals to English courtiers or politicians. He saw England as a key military asset in his Protestant ‘League of Augsburg’ against the ambitions of a Catholic France under Louis XIV. He really didn’t care much for the English, and they were never very fond of him.

William was highly intelligent, a talented diplomat and military leader, but he was not a charismatic man to the English. He was introverted, serious, solitary, asthmatic, five inches shorter than his wife, with a body described as weak and twisted. Mary was originally in tears when told she was to marry her charmless cousin, but she eventually developed a devotion and affection toward him that he was never able to inspire in his English subjects. The day he entered London, people waited in the rain outside St James Palace to catch a glimpse of him, only to learn that he had entered by another gate in a closed carriage. This was to be his style as King, never making the play for popularity, living quietly and out of sight. Mary was much more popular and better suited to the role of Monarch. Hers was the relevant royal claim and she had broader national support than William. William spent much time away fighting Irish rebellions and the Nine Years War while Mary performed the constitutional role of Queen in a court that always became duller when William was back.

While in England William avoided Whitehall and Westminster as much as possible, opting to live 12 miles upriver at Hampton Court where he embarked on a massive renovation project under Sir Christopher Wren (an unpopular project due to the costs involved). He preferred to work and eat alone and only ever loosened up around his closest Dutch confidants. Things were livelier at court when Mary was alive, but her early death from smallpox left England and it’s King in an awkward marriage. The lack of good relations with courtiers and parliamentarians proved a political liability in dealing the English nobility and landed gentry, who often opposed William’s military ambitions. It also shut down an important venue of cultural transmission. His desire for seclusion was a sharp contrast to his two predecessors, in particular his uncle Charles II who’s restoration court had been a vibrant atmosphere of culture and amusements. Dutch culture did not see any such efflorescence under William.

England and the Dutch Republic had much in common culturally and economically. Both were aggressive naval powers with budding trade empires, both militantly protestant and economically progressive. But relations between the two countries were chilly. They had fought each other in three wars during the 17th century, the last ending just 15 years before William and Mary’s accession. William’s arrival in London was welcomed by the protestant majority as a salvation from James II’s catholocism, but it was nevertheless a military occupation by a foreign power. English guards had been replaced by Dutch infantry throughout the city and at Whitehall. They would remain there for years to come. Dutch officers were placed in the top military positions. As time progressed and William’s war became the most expensive in English history to that point, subordination to Dutch military authority was generally resented by England and it's army. William’s social isolation highlighted the sense of foreignness that hung over him. He was greatly admired across the channel. By the end of his reign he had achieved a level of mutual respect with parliament and people, though never mutual affection.

Sources:

Mostly ‘English Court Life’ by Ralph Dutton, more generally from the ‘Oxford Illustrated History of Britain’ and Churchill’s ‘A History of the English Speaking Peoples’