Having just got home after working a 5 month contract on the Indy, as youth staff, I can honestly say it's a brilliant ship.
As many people have said, the number of complaints frequently outnumber the positive comments, as people are quick to judge, and in many cases there have definitely been 2 sides to the story.
I worked the Christmas/New Year period, which was our busiest time, and yes it did seem busy at times, but guests weren't queueing up endlessly for things, other than the guest relations desk on embarkation day! So don't worry about feeling like a sardine!
Just before I left we had an all crew meeting in which we were told that the Indy came out top in the fleet for overall customer satisfaction for 2012, so hopefully that will ease your worries a bit.