I will get on my knees and beg if I have to when I ask the developers to bring back the Safari Zone. I don't care if it's not as customizable as the one from Heart Gold/Soul Silver, nor do I care if it has a step limit like in generations one and three.
All I want is some type of Safari Zone-like attraction where I can go in, catch rare Pokemon, and sell them on the black market trade them to my friends for their rare Pokemon.
Even with that 'I don't care' thing in mind, there is one thing I ask for: don't bring back the swamp from Sinnoh's Great Marsh. Just bring back a traditional Safari Zone, maybe implement some elements from the Friend Safari Zone, and let's get some nostalgia in here.