We at Silicon Publishing have come to specialize in developing online design applications, with years of extensive work building web-to-print solutions based on InDesign (yes, pre-server) and Adobe InDesign Server. Because we didn't start with a product, but spent our first 9 years as a custom development shop, we have not tended to guide our customers on UI but have typically let them define what they wanted.
When we did create a product, Silicon Designer, we focused on the core common layer of what we had built for solutions, keeping in mind that the user interface would have to be quite different for different clients. We continue to see that different companies have wildly different concepts of what is important, even given similar document types/workflows, and there are differences between document types and business context that will in many cases require different UI approaches. We are glad we worked so hard at keeping the core functionality flexible with respect to user interface. Following are five UI considerations we see as we build online design tools.