Great post! I learned a lot and its interesting to see the drastically different directions Apple, Google, and MS are taking. Remember when everybody would just rip off everything Apple did? What would say the opposite of flat design is? 3D Design? Skeuomorphism? What would you consider Twitter Bootstrap? http://twitter.github.com/bootstrap/getting-started.html#exa...
We use greyed out buttons in two ways:
1. To gather data around interest in the feature. After clicking tell your user "thanks for the vote you just cast for this feature, we will notify you when its ready."
2. To indicate paid account only features
Congrats on your launch! Our first month, we had 9 paying customers, so very similar to you. But like the one commenter said, keep posting honest posts!
http://en.wikipedia.org/wiki/Manglish