"architect's work product is UML diagrams and dataflow diagrams"
IMHO this is one of the worst ever ideas in software development - largely as if you never actually get your hands dirty with real code and the whole messy business of getting it developed, deployed and actually used you never actually see what actually works and what doesn't.
I agree, but my point is that I think those UML diagrams are much more analogous to the work products of urban planners than architects.
Actually trying to live up to the title of architect and including blueprint level detail into those high level diagrams is asking for trouble.
I think that whole paradigm is a bad idea, but I also think that if you've already decided you're going to use one of those languages and run your project that way, it does make sense to have a person responsible for the high-level system design.