Yes -- by all means, if you have the time to do this, you should -- and it doesn't require much time, either. The Hidden Canyon is considered a hanging slot, and there's even a small arch there, too. We've done this short side hike a number of times, and it never gets old.
Agreed -- West Rim Trail will be pretty much all yours past Angels Landing. We've never found the West Rim Trail to be anything but easy walking, especially if you're used to trails in the Whites. Another thing to note is that the West Rim Trail forms part of the Trans-Zion Trek, or Zion Traverse. We've done most of this in sections, and if you ever have the chance, explore this. More information is
here.
ALSO...if you ever have a chance to visit this park in the winter, when no shuttle is running and you can pretty much come and go as you please, do so. It's a nice, relatively quiet time.
P.S. -- are you intentionally avoiding doing Angels Landing? Just curious; if you can beat any crowds on this route, it's worth doing at least once. If you get there too late in the day, the number of people trying this can make things...a bit interesting. I got behind one person years back who had fear of heights and literally froze in place, blocking the route. Not fun.