I sailed the Liberty in June of '11 and two months ago. Carnival Liberty is a good choice if you want a younger demographic and a more active nightlife. The bars, disco and Comedy Clubs were active every night. The new 2.0 upgrades are nice but not a revolutionary change. Guy's Burgers are very good but don't think they are the ultimate burger.
I'm not sure what your exact "Exotic Eastern" route is. It's a shame you don't get to go to HMC. It was an enjoyable beach day. If you go to Grand Turk I suggest doing a snorkeling excursion. There isn't too much "active" excursions there other than diving or snorkeling. If you want to kick back by the pool at Margaritaville or do some shopping then it's a good stop.
I know you'll enjoy the cruise and congratulations on your upcoming marriage.