The king is already mostly ceremonial. He seems mainly a stabilization factor for the country when both halves get a bout of separatism once more: He is the ultimate person every major politician talks to when nobody wants to talk to each other. The king does have some extra rights, but not too much, and the alternative seems worse.

King Albert 2 didn't want to become king but nobody else with enough capability was available. So it's not just a fun job.

But yes, the discussion to king or not pops up once in a while, and the general response seems to be we got much bigger problems.