One of and perhaps the hardest aspect of re-designing a product with a new visual treatment is selling the design both internally and externally. As a former manager told me, “design is pretty easy; it’s influence that’s the hard part.” This has to do with a savvy awareness of the internal political and power structure, as well as the cultural norms, and taking advantage of whatever chains of communication that are readily available, in an effective manner.
As for external selling to customers, massive validation plans and formalized processes that are heavy/burdensome in either time or money are not effective. Instead, it’s best to tap into a small alpha tester pool, informing them of the new design direction and soliciting input via emails, rather than a focus group. The email questions should be targeted for specific concerns if there are any; else you’ll get feedback like “that’s nice” that vaguely suggest but not concretely advise.