To state the obvious, Group D is going to be insanely competitive. Canada, Germany, and Jamaica are all upgrading talent from 2010 and Poland and Ukraine will be above-average good. I've already covered two players Canada is getting, I'll get to Germany soon, but for now I'm going to focus on Jamaica. From what I've heard, they're not losing anyone significant from the 2010 squad and they're bringing in at least a couple quality players - possibly more.
Kevin Holness should be returning. He says he needs to be back in shape, but from what I've watched his conditioning is more than what it needs to be to compete. I'm guessing its 95% that he'll play. Saskatoon's Mark Korthius should also be returning. He had to miss a couple games in 2010 but he's back on the roster for 2011. Regina's Garrett Peters should also be returning, provided he finishes exams at Trinity Western in time to make a difference.
Two major additions are supposedly the Prime brothers, Karmal and Amilcar, from Saskatoon. I've personally never played against either of them, but I've heard from numerous people that they're solid additions. The only other things I've heard are rumours of more former Canada Games players, but nothing definite and no actual names.