I admit I am somewhat new to cruising and very new to NCL, so I can't answer all of these questions with confidence, but here is what I do know...
--Club Balcony Suites get a few extra perks like one free laundry service, little foods and beverages brought to your room twice per sailing (for 7-day cruises), a slightly bigger room, bigger bathroom and shower with body sprayers, a second sink, and early booking for specialty dining (obviously the last one doesn't apply if you book at the last minute)
--You will definitely miss out on prime dinner reservation times, vibe passes, spa passes, and reservations for popular shows. With that being said, you can always check with guest services when you embark and ask if anyone has made changes to their dinner/entertainment reservations. I've also heard that if you wait in the standby lines for the shows, you will almost always get in. For specialty restaurants, you might not get so lucky and you may have to eat late, but the complimentary restaurants are always available and don't require reservations!
--I think my overall advice from the countless posts I've read so far and social media groups I've followed is that if you are prepared to be super flexible and enjoy a more simple cruise without all the frills, you could still have an awesome time. There are a lot of wonderful complimentary options available as part of your cruise fare that you could still have an incredible time, you just may miss out on some of the premium included options that other cruisers who booked months ago are enjoying (like specialty dining at prime time and popular shows). If you go in with all that in mind, I think you could still have a great time!