Not a fan of the spiral of doom personally. It's a bit of a gimmick that has come over from a couple of american courses from a few years ago that only promotes single file racing with a pinchpoint in the centre. Plus it can be quite confusing for both fans and riders to see where a rider actually is in the spiral and gauge the distance.
Agree, I've raced courses with spirals and the typical thing that happens is at best a slow single file or worse a big bunch of tangled up riders. Not fun at all and not particularly technically challenging either.
On the other hand, long sand stretches, curves in sand and steep off-camber sections are great in testing riders skills - like at the Belgian championships. More of that.