Valid but I think there is value in having a manned airship (more science performed, technology development, operational experience, etc...) in the HAVOC proposal.
IMO, HAVOC and specifically the development of the transfer vehicles and ideally a system of shuttling continuously vehicles between Venus - Earth - Mars is viable crawl-walk-run strategy for inner solar system exploration.
First mission(s) to Venus for tele-robotic sample collection and concept development (atmospheric entry would be awesome but not necessary) then leverage that experience for Mars orbital / Martian moon landing missions, building infrastructure (orbital & surface) for a landing in the mid 2030's during these missions in the 2020's.
http://www.popularmechanics.com/space/moon-mars/a17552/phobos-landing/
