A roleplaying game that doesn't present an interesting role to play is one that is failing in the one thing that it has to do right.

This is, for example, the reason why Bound by Flame was something I enjoyed despite being a very rough-around-the-edges indie game.  The character I was playing was something I felt compelling.

And that's exactly what Legion is ultimately missing.  It doesn't have the key thing to bring everything together.  It lacks a decisive and coherent role for its protagonist.