Started approximately in the late 1980s, exoplanetology has up to now
unveiled the main gross bulk characteristics of planets and planetary systems.
In the future it will benefit from more and more large telescopes and advanced
space missions. These instruments will dramatically improve their performance
in terms of photometric precision, detection speed, multipixel imaging,
high-resolution spectroscopy, allowing to go much deeper in the knowledge of
planets. Here we outline some science questions which should go beyond these
standard improvements and how to address them. Our prejudice is that one is
never too speculative: experience shows that the speculative predictions
initially not accepted by the community have been confirmed several years later
(like spectrophotometry of transits or circumbinary planets).Comment: Invited review, accepte