Don't be afraid to throw out something from your game as you are testing. PlaneCrafters started out as strictly a draw, then play card game. It was ok, but I wanted to give the players more choices. I came up with a mechanic that gave players a couple of options, and restricted a couple of others, but those options changed each turn. Here is an image of the second version of this oh-so-clunky mechanism. It was meant to emulate the spinning of a propeller.
With this mechanism each player had a marker indicating which role they chose. Following players were not able to choose an occupied role, which, in the original only gave them a choice between two. You were required to move your marker to begin your turn. See what I mean? Getting clunky.
Turns out, this wasn't such a fun way of doing things. This mechanic had to go, but we had to have a way for players to make more decisions. That's when we came up with the idea of hiring employees, that would stay in your personal factory until the end of the game. Now players had a way to make decisions about how they wanted to build their airplanes, and they now started to identify with the employees, like they were really building a company to compete with the other PlaneCrafters.
I really like the idea of the spinning propeller giving special abilities based on what parts are revealed. This implementation, however, is not the way to accomplish it. Have you seen spinning mechanics such as this which worked successfully? Do you have a favorite? Let us know!