Over 25+ years, I have gone from a rock wall, to islands and finally to more minimalist and negative space type reefs.
The negative space requires some thought but if considerations are made it can be done in little time and without special tools. My latest design was setup in about 30 minutes and did not require any glue or epoxy.
This open setup allows for optimal flow, space for coral growth and room for the fish to stretch their fins. There are also many caves for the fish to sleep in after dark.
At the end of the day there is no wrong way in designing your reef. Everyone is going after something a bit different than the next reefer.
The new setup (three weeks old today)
Below you will find pictures of my setups over the years: