Somewhere, I seems to recollect an answer of Christian, announcing that they are working on further refining the user interface.
Please let me say that I hope the re-design will follow a minimalist approach: stylized icons, smaller interface elements, the greatest integration with the style of the Mac user interface.
Often, software developers consider adding big, three-dimensional buttons as “improving the interface”. In my view, this would be a way of stealing space to information, and introducing distraction.
So, I would be happy if DevonThink’s look will follow a different route.
Not being a designer, I’ll have very little more specific to tell you. In general, I guess that stylized icons are better than more realistic ones. For example, the QuickLook and Gear icons you took from the Finder have the advantage of being clean and take little space.
The magnifier glasses, on the contrary, while trying to be realistic are simply difficult to read (being the encircled symbol hidden by the big surrounding structure). Also, I would like if you could avoid using the big red button to close the side drawer, and use the small encircled ‘X’ that is common to other apps.
Safari is a good source of modern, minimalist icons. There are no colored, realistic items, but just flat, unobstrusive dark icons, that are as easy to understand as road signs.
Not to be critical, but agree with Paolo’s general point. Leap and Pathfinder both have cleaner, slicker interfaces – though no one can touch DT’s functionality!
If I may add: my preferred style of icons is the iPhone style. Really basic figures. No space kept. Immediate to understand. But I don’t know if they match a Mac’s application, or they cause disharmony and incoherence.