I do like balsamiq, it's a great tool for roughing out a design, but I don't see how it addresses any of the points I made. Dynamic layout - as far as I can te

I do like balsamiq, it's a great tool for roughing out a design, but I don't see how it addresses any of the points I made. Dynamic layout - as far as I can tell balsamiq uses an entirely static layout, unless I'm missing something. Viewport preview - again can't see how it helps with this Text dimensions - have to be specified in pixels, not ems. and these are just examples of some features that are missing...