In 3DSmax there was an option you could check so that when selecting a very complex model or group, the items you selected would be visually converted into a bounding box, just while you were manipulating it. I’m wondering if there is something like this in Rhino?
Else
A way to turn the edge highlights off when selecting an object?
There isn’t currently, no. We have several feature requests on our list for this - I’ve added your vote on the oldest of those that I could find - RH-17045.
-wim