I like Obi. But I'd let him do what he does best - Box Safety.
From PFF:
Best box safety: Obi Melifonwu, Connecticut
At 6-foot-4 and 223 pounds., Melifonwu is capable of erasing tight ends with his size and physicality in a way that less than a handful of current NFL safeties are capable of. He is also a viable run defender, capable of taking snaps at linebacker based on personnel and game situation.
Best versus the run: Obi Melifonwu, Connecticut
Melifonwu is a solid wrap-up tackler who consistently breaks down to make open-field tackles and is capable of delivering huge hits coming forward. His excellent run-stop percentage ranking was already highlighted above, but he also finished 17th in the FBS in tackling efficiency, and considering his size, awareness and technique, this should translate well to the next level.
Best in center field: Malik Hooker, Ohio State
While there are a number of strong contenders for this category, this is what makes Malik Hooker a viable top-20 pick. Hooker has an uncanny ability to track the ball in the air, and has the size and explosiveness to consistently outplay receivers for the ball in the air.
What's interesting though - we may very well, at times, "flop" our Single High (Box goes high, High goes to Box). In situations like this, SS that can also go high increase in value. Players that come to mind:
Adams
Melifonwu
Peppers? - hard to tell, imo
Maye
Hill
And of course:
Our very own Eric Reid, who is already being asked to go to the Box safety role, but could "flop" to single high - he has range)
Our very own Jimmy Ward, who probably played his best football in college in the Box, but he's a little small to be the box S on the regular)