He ignores several of Melian's statements completely as if she were thin air, while at the same time hiding behind her girdle the whole time, imprisons his adult daughter, while he does not search for her (in the texts) when she might be in real danger, refuses Daeron's intercession for Luthien, refuses help and refuge to the victims of war, does not even morally support the fight against Morgoth, forbids languages and is all pretence while never doing anything for anyone else. Enough? If we remove the few achievements the texts give him, his character descend into such a depth of jerkdom that it will be difficult to recover it back when we need it to be taken seriously as a kings worthy of being followed if we do not give him something to recover ground with. Just accepting Luthien's choice of husband when becoming aware that she is an adult and completely able to do what she wants and e.g. move out and live on her own with her lover - out of fear of losing her himself - does not in itself rehabilitate him enough.