If that’s what you think how bout the other way around? How can you evaluate content without design? No typography, no colors, no layout, no styles, all those things that convey the important signals that go beyond the mere textual, hierarchies of information, weight, emphasis, oblique stresses, priorities, all those subtle cues that also have visual and emotional appeal to the reader. Rigid proponents of content strategy may shun the use of dummy copy but then designers might want to ask them to provide style sheets with the copy decks they supply that are in tune with the design direction they require.
Or else, an alternative route: set checkpoints, networks, processes, junctions between content and layout. Depending on the state of affairs it may be fine to concentrate either on design or content, reversing gears when needed.
Or maybe not. How about this: build in appropriate intersections and checkpoints between design and content. Accept that it’s sometimes okay to focus just on the content or just on the design.
Luke Wroblewski, currently a Product Director at Google, holds that fake data can break down in real life:
Using dummy content or fake information in the Web design process can result in products with unrealistic assumptions and potentially serious design flaws. A seemingly elegant design can quickly begin to bloat with unexpected content or break under the weight of actual activity. Fake data can ensure a nice looking layout but it doesn’t reflect what a living, breathing application must endure. Real data does.
Websites in professional use templating systems. Commercial publishing platforms and content management systems ensure that you can show different text, different data using the same template. When it’s about controlling hundreds of articles, product pages for web shops, or user profiles in social networks, all of them potentially with different sizes, formats, rules for differing elements things can break, designs agreed upon can have unintended consequences and look much different than expected.
This is quite a problem to solve, but just doing without greeking text won’t fix it. Using test items of real content and data in designs will help, but there’s no guarantee that every oddity will be found and corrected. Do you want to be sure? Then a prototype or beta site with real content published from the real CMS is needed—but you’re not going that far until you go through an initial design cycle.