Looks like it has joined the ranks of other European destinations which are wanting to reduce the day-tripping mobs.
We stayed 4 nights (day tripped to Ghent) and loved it. Busy? Sure but only in concentrated areas, and you can explore a quieter atmosphere of those early in the morning or later in the evening if you've booked a room. During peak hours, walk just a few blocks away from those places to find breathing space. I also don't recall the art museums and some of the other interesting attractions being overrun at all.