The noble phantasms look nice, but overall he's still probably the weakest servant not called Caster in melee combat. I'm not sure if he's meant to be crossing blades with anyone but right now Saber, Lancer (I hope), Archer, Assassin (if Hanzo), and Berserker should be able to fairly easily solo him in melee without the use of noble phantasms. That isn't taking his Roc into account, nor his insane luck, but if he's meant to be proficient in close quarters parameters of D/C/C aren't gonna cut it.
In all honesty though from what I know of his legend Sinbad wasn't much of a warrior, so it's probably appropriate that Beowulf, Arjuna, Hanzo, and a Berserkerfied Macbeth can beat him in melee. I dunno, depends on what you're going for.