The difficulty of converting a Photoshop design to an actual UI reminds me of this passage from Paul Graham's essay "The Power of the Marginal" [1]:
> For example, it recently emerged that the famous glass artist Dale Chihuly hasn't actually blown glass for 27 years. He has assistants do the work for him. But one of the most valuable sources of ideas in the visual arts is the resistance of the medium. That's why oil paintings look so different from watercolors. In principle you could make any mark in any medium; in practice the medium steers you. And if you're no longer doing the work yourself, you stop learning from this.
In the case of mobile app development, it's probably best to let the constraints and idioms of the platform, which the developer knows best, steer the design. So maybe part of the solution, contrary to what the article suggests, is to further collapse roles; maybe the developer should do the design, too.
A lot of comments in the thread are commenting that the developer should be able to slice up PSDs, but why not go further and be responsible for the design and interaction. It requires empathy for the user and, let's say 100 hours spent on understanding fonts, colour and layout.
The constraints of the platform should absolutely guide the design. Fight those constraints and the app will feel weird on the platform.
Most designers won't know the constraints of the platform, or won't care; they want to make a design that's unique and beautiful and all that. The client (or any human being) will look at the pretty pictures and love it. The eventual user of the software _won't care at all_.
Designers make pretty stuff that demos well. Those designs are usually a lot more work to pull off in code, though. In the middle of implementing those designs, all I'm thinking is, "What a waste of money. No user is going to care about this [animation|screen transition|custom look|beautiful settings screen]."
This applies to web and mobile and desktop apps.
Look at the apps you use everyday. They're probably boring to look at.
At the least, if you're in the client position, get a designer and developer together at the same time to hash out the app. You can probably get something that looks decent, works well and costs less.
> For example, it recently emerged that the famous glass artist Dale Chihuly hasn't actually blown glass for 27 years. He has assistants do the work for him. But one of the most valuable sources of ideas in the visual arts is the resistance of the medium. That's why oil paintings look so different from watercolors. In principle you could make any mark in any medium; in practice the medium steers you. And if you're no longer doing the work yourself, you stop learning from this.
In the case of mobile app development, it's probably best to let the constraints and idioms of the platform, which the developer knows best, steer the design. So maybe part of the solution, contrary to what the article suggests, is to further collapse roles; maybe the developer should do the design, too.
[1]: http://paulgraham.com/marginal.html