Polish up error messages
The transition from Beta2 to released software is, in my oppinion, very much dependant on giving the user informative error messages.
I noticed the following two error messages when trying to give MapTiler an indexed PNG: Float expected, or index out of bounds. Only by really thinking through the problem was I able to discern that the PNG was suposed to bin in RGBA format, and processing/optimizing done only on the output of MapTiler.
The error messages has been significantly improved in the new version of MapTIler. Check http://www.maptiler.com/