Yeah the map is an absolute blast but people complain about it due to multiple reasons.
Too many infected.
This is actually what makes the map so fun to play. On Chernarus I can run into any place without using any part of my brain and I will survive just fine. I can't do the same on Deer Isle. People been wanting a lore wipe for such a long time now and while Deer Isle is still in the current lore, it provides the feeling of something fresh with the amount of zombies that are around. Having to sneak into place and actually use my brain when moving around is so much fun and engaging.
Map is not finished.
I do agree that the map is still WIP, no one was hiding that. However, it is mostly the north part of the map that is lacking. There are points of interest all over the map, that make Chernarus look like the most boring and stale map. That is actually the problem that Chernarus has, is that while finished, most towns are just copy and paste. There are barely any place on the map that are amazing and set a nice stage for RP. If there are they are all set in opposite points on the map or remote ones that barely anyone goes to. Compare that to Deer Isle, where the main town itself has so many little secrets and places to explore that are not in eye sight. And that is only one town. There are multiple spots around the map that look sick.
Most RP that I got from Deer Isle has been pretty good. Interactions feel different and I enjoy finally exploring places that I have never been before and finding out the cool secrets of the map. Of course Deer Isle does have its issue and most of them aren't even because of the map. My main issue with it has been changing from S1 character to my S2 one. While the timer is 6 hours it is still plenty of time and does not encourage much people to try the map. I wanna play on Deer Isle but I also have to hop on Chernarus and play with my group. This wouldn't be a problem if staff could just reset the timer for such characters as it is as clear as day that there is no alt abuse(reason for the timer in the first place), but for whatever reason is not so easily possible.
Overall, I enjoy playing on the map and find it more fun than Chernarus. Hope people pick up on it more and realise the beauty that it holds.