I would try to build some kind of navigation, as "related assets" just won't work as you state. Even with filtering what are the paths that users take to get from one asset to the next? I would build your displays and navigation between displays based on that.
E.g. in a more standard factory i typically use navigation up/down in hierarchy, and forward, backward in the product streams, or group related assets together, e.g. all turbines on one overview page.
It is interesting to see that the new "PI VISION 2017" has no search in the display!!! It has only again a drop box with a scroll function and click next page thing.
I just cant believe we are the only ones with such a requirement ..... there are no words to explain the how disappointed we are OSISOFT!