A dormer’s floor space depends on where the roof gives you headroom

How much usable attic space a dormer adds seems to depend on the existing roof pitch and framing, not just the dormer’s footprint. A dormer might make part of the attic comfortable to stand in while leaving much of the floor under the sloped roof hard to use. Raising the roof could create more consistent headroom, but that seems like a much bigger structural change.

What would you want an architect or structural engineer to assess before choosing a layout? In particular, what does a roof raise typically require them to check about the load path, foundation capacity, and lateral bracing? I’d also want to know early whether zoning height limits or exterior design review could rule out either option.