Aqua is already a success because it challenges the way we look at computing and our expectations of a computer. I think the hardest aspect of adapting to Aqua isn't for the users, but for the developers. Apple is asking them to rethink how they conceive and build software. They've asked them to stop thinking of image and size restrictions. They've asked them to break from the idea of what an icon represents and what it can do.
Software developers can no longer view themselves as just code-cutters.
Apple is asking developers to evolve with Aqua. Aqua is art. It requires that we learn to embrace ideals and concepts that illustrators, video artists, editors, painters, animators, composers and publishers have been using for years. It is no longer enough for software and hardware developers to write code and build solutions, now you have to actually embrace media and artistic concepts. Looking back on the release of the iMac, iBook, and Cube, the organic design of the hardware and the resemblance to OS X was no accident.