Atm, Isla Event is one of worst, least played stuff in the game by most people (that aren't whales), while the rewards it usually gives are very cool, the how it plays is awful.
You're given a list of animals that can only be used, and most time are animals you never cared about, either because you build your team or raid team based around X or because is a recent addition and you don't have it level 89028 Super Saiyan God Super Saiyan with 20 boosts on attack and 10 on speed with a masamune on each hand.
Imo, the Isla Event should be reworked and I have two proposals:
Option 1 -Make it so all the animals that can participate are level 26 (event ones will stay same level), boosts can stay, that way it rewards more the skills rather than the amount of wallet people have spent on the game.
Also make the event to have few more levels BUT each 5-10 levels, add a healing spot to heal certain animals.
Option 2 -Make it so ALL the animals you have CAN PARTICIPATE but make it so the animals of the list are EXTREMELY BUFFED (But please don't make it so unless you use em, you can't win, just make it fair for everyone, but if you own those at max level, you'll finish it easier), like +100% damage inflicted and -50% sustained damage, so all your stuff can play but if you own certain one, it becomes a monster in that event, that way is fun to play for everyone.
And that's all for now, I think Isla Event could be amazing, but needs some tweaks :3
now I'm at it, pls nerf ALL PANTHERAS dodge abilities it's awful and have no counterplay