I'm not sure that, "What is it you can live without?" is the right way to plan to make your choices.
I think the right way is, "What is important to me?" Some of these things benefit from advance planning, such as picking the right shore excursions or choosing a night for Palo. But for most things, you can make choices on the spur of the moment.
You'll have to "live without" most of what's on the Daily Navigator each day. Between the early big evening show and your late dinner seating (or between your early dinner seating and the late big evening show) there's about 60-minute gap. There are at least a half dozen things going on during that hour — family cabaret shows, family game shows, pin trading, sports trivia, lounge entertainment, and more. Or you can relax in your room, on your verandah, or in various indoor and outdoor locations throughout the ship. Again, you can't do it all.
I'm not sure you should worry about what other people opt out of doing. Personally, I can live without anything having to do with spectator sports, so aside from taking two minutes to see the ESPN Club, I didn't devote any time to any events there. But for a big sports fans, my lack of enthusiasm for spectator sports would be puzzling, and any advice to avoid ESPN would be meaningless.