Rotating GMs

Funny thing happened - we decided to rotate GMs for our new Rogue Trader campaign, after I asked for some time off from GMing this system and theme. I was asked to create a character, and walla! I was min/maxing like hell and diving into the rulebooks looking for the most potent combination of skills and talents to impress my friends at the table (who am I kidding? I wanted this poor GM to get a taste of his own medicine...).

Diving into rulebooks? Optimizing? exactly what I, as the GM, ask the players NOT to do. I keep on going on rounding the characters, thinking about role-playing and character interaction - but as soon as I got the Player's Handbook, the first thing I looked for is the most damaging weapon available...

It was an eye-opener. Almost to the point were I was tempted to say: "Forget it! I'm GMing it!"

It occured to me that I wanted some time off GMing in order to improve my GMing skills. I've been GMing since I remember myself, hardly being a player at all. So rotating GMs, at least for a short, mini-campaign or a serie of adventures is a great way to view the table from another angle. Also, by playing with your "Ex-Players", you are now exposed to all that player talk, those little conversations you ignore as a GM, either because you are busy reading your notes, or because they take place when you are not there...

By rolling up a character, it suddenly occured to me that I want this character to be successful and useful. I wanted the other players to feel that I contribute to the group, I wanted to show off my role-playing skills and bring this character to life. No wonder I want the best possible armor, I want this character to live to see another day!

So maybe the key to being a good GM, is being an occasional, good player?
Can you be a good DM without playing at least part of the time? Or maybe you don't have to be a construction worker before being a good architect?