Europa's energy potential may be low, but Titan is far colder and does not have tidal heating. Titan is getting prime treatment with the current mission. It might get even more in an extended mission. Cassini is far more capable than Galileo I believe because it is both newer and in far better shape. Europa deserves a second look at least as good as Titan is getting now unless Cassini finds something really boosting Titan beyond Europa in life potential. A good ice rover design for Europa should work with little modification on Titan IMO. Europa's environment would seem more demanding to me with no atmosphere for protection and higher radiation. They have similar surface gravity.

Regards,
Mark