They only look like that during crew drills when you can't be out there. If you zoom in, you can see it says "Crew Only" or something to that effect. They are usually not shut up tight like that.
The inside doors were propped open on our cruise. I didn't check them on the first day or during the drill but they were open every time we passed by.
You cant shop in Mickeys Mainsail unless you wait until midnight when everyone else is asleep.
Definitely do NOT go after the show. That's when everyone goes in. We looked around, noting what we liked and came back twice to purchase. Once we popped in at about 10 pm and once during the day on our day at sea. No one in line at the cash at those times.
We actually liked that the bars and lounges were scattered about the ship. What we didn't like was the small size. You have to get to the venue more than 15 minutes ahead of an activity if you want to get a seat. We tried a few times to get coffee at the Enchanted Sword, and the other one (can't recall its name), and it was always so busy with nowhere left to sit that we just left.
We liked that the restaurants - with the exception of Arendelle - were divided into smaller pieces. Made it feel much more intimate and less like a banquet hall. Even Marcelline Market had little pockets of quieter spaces to eat, and there were even some spaces on deck that were a bit apart which was nice.
I didn't like the adult-only pool and pool area, but I figured since this was a four-day cruise, we wouldn't be spending much time there, so it wasn't an issue for us, but it might be on a longer cruise. I was very sad about how small the Cove Cafe was because we used to spend a lot of time in the analogue on the other ships, but we were there with our friends, constantly darting about the ship doing other things, so, again, it wasn't much of an issue although perhaps we might have spent more time there if it was larger.
We did find the layout confusing - thought that may be because we're used to the other ships - but we did the ship tour and it was very useful for orienting oneself, using the carpet and decor hints.
Although I wasn't thrilled with the storage layout in the cabins (why did they remove the drawers and substitute shelving?), it did help it to feel larger than the Dream/Fantasy (both of which definitely feel - and are - smaller than the Magic & Wonder) and thankfully they went back to the sliding closet doors instead of the ones that open so that block someone coming out of the bathroom or into the room. Lots more USB ports and plugs in the cabin which was much appreciated! And although the phone was a little awkward to use, I liked how it was out of the way and not the first thing I knocked off the bedside stand every morning.
The app definitely needs work. The chat function only worked intermittently. Sometimes it would tell you that the message was undeliverable and you'd have to reboot the phone to make it work. Sometimes it would say sent but was never received. We tried to play the Uncharted Adventures and eventually had to go to Guest Services to find someone who could make it work for us. We played a couple of parts of it but it was glitchy. If they could fix the bugs, I can see how it could be better than the Midship Detective game but it needs work. We did find that Apple iMessage worked more reliably for chat than the app. The rest of the app is fine - it notifies you when things you've marked are upcoming which I liked. We booked the ship's tour on the app and it was easy and fast to do. So there are some improvements in the app over previous cruises we've been on, but it still needs a bit more debugging.