Cursed mark was bullsh*t, plain and simple. Please note that Sasuke has not sprouted hand-wings, the extra flight abilities they granted him, nor the inverted eyes and hair since having his seal removed. Therefore, it clearly was NOT ENHANCING ANY NATURAL ABILITY OF HIS!
Although after seeing him use the wing to grab, the snakes and wing to block attacks, and the snakes as a substitute wing, you can't deny that he showed incredible skill in wielding the mark. If anything, it's more akin to the Kyuubi sealed in Naruto. It's the exact same thing, actually!
I know it's been said so many times before, but it makes the fact no less true now: Sasuke won by using the fourth great power awakened by the Sharingan: Plot Armor. If you think for a second that at the end of that fight he should've been able to summon a creature as large as Manda AND cast a Genjutsu on him, then you are deluded.