I dunno; unless it's an extremely trivial case (single table, no joins), they are still thinking about this: does this new form make sense as a standalone form? Does the functionality overlap with a current form (and if so, should we rather refactor the workflow than add a new step), etc.
There's also nitty-gritty stuff: should I make this a common function callable by other form-generating code, or keep it as a single-caller function?
More often, when writing code you often get a good sense of what is currently broken in the design. In greenfield, you can just go ahead and modify the design. In brownfield you are going to try to minimise the modifications in design as much as possible. This is still thought.