Let's begin with OSRS Gold wilderness boundaries. Before 07 there was no safe zone. This is the most important element of the current wilderness design. It has safe zones. While you might think that they should be retained, they hinder the flow of current pvp fights. It promotes the safety zone, but also focuses on fighting around them.
By adding restrictions, this defeats the purpose. The issue is whether we will see a new wilderness design in BH worlds, or the old one. The issue with the modern activities in wildernesses that were not there before is another. Are they staying or going, and what effect could this have.
Personally I would be favor of moving all the minigames (Clan Wars, FOG and sealing off Deamonhiem) to different locations, however the most difficult part is the 3 quests. Defender of Varrock as well as Summer quests both contain large wilderness areas. In my opinion, the best solution would be to instill the entire quest. What exactly do I mean by that? You are completely on your own once you reach the quest start point, or when you enter the wilderness in the story of the Defender of Varrack. This would change the story slightly, but it won't alter the quest in any way.
Green Dragons and Buy Old School RS Gold Zombies, Chaos Ele, and other such things should all remain the same. But, I believe the most effective training location is a bit risky. However the Corporeal beast is an interesting aspect, and I'm sure it would be enjoyable to send runners crashing to the cave the boss's mechanic is unique in RS because you'll be banking a number of times due to the extremely risky nature. It could be more attractive if the entrance were relocated closer to the wild.