I really don't get the timing of announcing and funding this mission, other than an ESA checklist to visit all the planets. With MESSENGER just flying by and not orbiting until 2011, why plan for a mission that on it's heels. There are so many more worthy missions that would complement our current knowledge. I could see planning a new mission to Mercury dependent on what the MESSENGER mission reveals. But my goodness, I wouldn't want to plan a new mission until at least a year after MESSENGER orbital insertion in order to study the science it reveals. How in the world can you know if burning questions arise from MESSENGER that might require novel instruments from the next space craft? Maybe, the fact that it is not planned for launch until 2013 (2017 arrival) means that its early level of funding is more of a study than a real mission.

Still, I would think a new mission to the Jupiter system (Europa!,etc.) or another visit to the Saturnian system (Titan!) would have much higher priority. A joint mission with USA with lander (or even dirigible on Titan) and orbiter would be a fantastic new mission to use scarce science funds. Unlike BepiColombo, this would be leveraging recently acquired knowledge to design the next logical mission.

I thought ESA's Venus probe is/was a great mission because no one had visited Venus for a very long time. Great science could be done. But, I really can't understand this mission to mercury other than some checklist from some bureacratic plan that was probably crafted 20 years ago. Of course I am often baffled by the way government spends our scarce funds (e.g. Space Shuttle, ISS white elephants), so I guess this should come as no surprise

http://news.bbc.co.uk/2/hi/science/nature/7195374.stm