I doubt Oro gives his seal to anyone but a select few.

Kabuto is strong, but I don't think he's capable of growing in strength rapidly like Sasuke or Naruto.

The potential is what Oro was looking for. It's basically just a Darth Vader thing. Oro shows Sasuke just a little bit of the power, and gives him an incentive to seek out more.
The seal will multiply his already rapid growth rate, and if he can survive it, he is fit to become Oro's new body.
Kabuto, who's strength is probably more based on experience, probably can't handle that ultra fast increase in strength.