if we are going to consider the dmg on melee, id say the most worth would be evang, som, tome and djinn due the lack of physical attack power the users have. however few people that use those melee anything
on my oppinion, the best to overup is mjol due the lack of special skills that smiths have, squeeze attack power through anything is a must. mainly if you intend to pvp/woe
the rest of them arent really needed to +10 since as already mentioned, you can kill the same with one +4. however if i were to up them to +10 id do it on a TF, nib and mjol