It's all good.
After reading and posting in several of these scrubber threads, I find they often descend into a fight over which is better (ATS or Skimmer, Adey or SM etc.) and then hard feelings. A pound of prevention....
Oh, I would not limit that behavior to just scrbber threads!
Most of the development has been in inexpensive design after SM. I have access to a high end CAD system and a machine shop so I like the full fledged ATS but if you want something cheap and simple SM's are hard to beat.
As you know Refugiums and deep sand beds are an extension of the more natural way of cleaning the water after Adey, Tyree and others but not too much is new that I know about.
Yep - All of these have been around a long time for sure. An dno doubt they work for some folks quite well. Every system has trade-offs, and we all are looking for the least amount of down-sides for our individual needs/style of reef-keeping.
As you also know, cheato in the sump is getting to be very popular. It's simple and builds a little trust in algae.