I'm going to throw my :twocents: out here and see how it works, I myself have a Diamond Goby and he is crazy fun to watch, cause he is constantly shifting through sand, one thing they do do though is make piles and crazy big tunnels. Mine has made tunnels all the way throughout the rock work in my 56 gallon. I had all my rocks glued together so I don't expect a slide, but he has done some work, I'll see him disappear at one end and pop out on the other. Really cool fish to watch.
From what I've read and learned from other reefers and my trusted LFS guy is that the smaller gobies that shift sand, don't move it around as much, cause they stay small.They will just create little piles here and there. So I would think that it would really depend on your preference. I love the way he keeps the sand and he does stir a lot of the excess crap and food up that doesn't get eaten so it can be sucked into the sump, but he has bugged some corals on the ground with how much he can spit out.
Overall my bigger guy is a very cool fish..he will also get pretty big, most of the small ones stay pretty small.