Mark, I pretty much agree with you, but feel singles only players might get the idea that doubles is monotonous.
While I agree those are "The big 3", lobbing skills are extremely important. And, when the lobs go up, your overhead comes into play every single time.
Returning is much more difficult in doubles because of that pesky opponent camping on the net, you need to have all the tools, chip and flat/topspin off both sides. As you correctly observed, good doubles players hit 3/4 pace with spin. They also have good placement, which makes returning even harder. now, let's talk about the lob return; the driving first volley from just behind the service line, the split step needed to accomplish that shot, etc. etc. etc. Did I mention that around the netpost (or close to it) shots arent uncommon at all?
That's why I like doubles...... IMHO 1000% more strategy/tactics/variety necessary....
Not to say singles doesnt have that too..... like chess, you have to play the point about 2 or 3 shots ahead to effectively open up the court for a winner.