Mercury must be visited...why?
1) Because extrasolar planets were discovered which are as close or even closer than Mercury to their respective sun.
(comparative science).
2) Because Mercury has an iron core that occupies 40% of its volume (quite unique and not according to the planetary formation theory in our solar system).
3) Because of an unexplained magnetic field (molten core even for its small size?).
4) Solar wind could compress Mercury's magnetosphere all the way to the surface.
5) Because of icy poles...
Phil, you don't think Mercury is worth it?
Raoul