This is a meta tag . Searching on it is useless, and it's frowned upon in the stack exchange network
Just look at the results of a search for "design review" https://electronics.stackexchange.com/search?q=design+review The hits fall into a few categories.
The most common, to me at least, is just plain mediocre questions. There's also a class of good questions that are undertagged, which decreases their value. Many are good questions that have some very good tags, and adding a design review tag probably won't make them better.
For example, let's say I'm interested in constructing an rf circuit as a pcb, and I scan for design review questions.
Search on "rf" : https://electronics.stackexchange.com/questions/tagged/rf
Search on "rf design review": https://electronics.stackexchange.com/search?q=rf+design+review
Search on "rf PCB": https://electronics.stackexchange.com/questions/tagged/rf+pcb
The last looks to be the most useful search to me.