That depends on what you mean.
If you literally mean his ability to use intangibility on himself, then I don't think he'd be that much weaker. He'd still be able to use Kamui to kill anyone else, and I'm sure he could dodge attacks for the most part.
If you mean his ability use Kamui entirely, then he'd be a weaker Uchiha unless he had another Sharingan power. Then again, if he has access to Mokuton and the Rinnengan, it wouldn't make much of a difference.