While we wouldn’t end up on anybody’s list, two other 3504 mentors and I essentially did this. We’re grad students who joined the team this year and won’t be around next year. It’s a strange experience, because trying to change too much can backfire and trying to teach too much can result in too much information to grasp (and you won’t be around to reinforce it later).
Yes, having new technical knowledge on your team for a year is great, and introducing new ideas and new ways of doing things is great. But I think the biggest impact a person can make in a single year is in team culture. Any team where all the members are constantly striving will do just fine.
That said, I do think a lot of the folks mentioned in this thread would make big positive impacts on team culture as well as technical excellence.