It seems people play Hunt, Arena and Defend and as a Monster Rescue Mode is the easiest game to play. So here are my thoughts to make Rescue easier to play as a Hunter as well as still being able to win as the Monster:
1: Strong Survivors
They should be able to put up more of a fight. Giving them the ability to protect themselves like a Assault and deal out damage like a Support. (I don’t know for sure but they do have Jetpacks right?)
2: Quick Revives
Hunters should at least be able to revive colonists a little faster just for that small balence issue.
3: Fast Plays
Hunters should have to retrieve 3 survivors giving only 1 colonist at wave 1, 2 colonists at wave 2 and 4 colonists at wave 3. Monsters on the other hand still have to kill 5. Giving them less time to search around for food to evolve and allowing themselves to be forced to fight. Giving Hunters and advantage.
I think this concludes my suggestion on how to make Rescue a better balanced game.
Thanks for reading!
TL;DR: You can leave JK