That could work, good call on the second paragraph - some aspects of the wildy are remnants of a distant past, a rework wouldn't go amiss. Let's be bluntly honest with each other here, very few people have reason to go out into the wildy if they dislike PVP, and will mostly bring their naked bodies for clue scrolls or minimal-loss gear like 3-item + black dhide for bossing. Look at how many people jumped into the wildy compared to before when they had opt-out PKing introduced in RS3, it shows the majority's disdain.
Currently, it's mostly PvP-heads fighting each other with an occasional naked or almost-naked going in because "I have to for this scroll/this boss". The "small fish" will have nothing good on them, meaning the big fish are generally starving - all hanging around bosses or other popular areas, changing channels to find them. If I wanted a change-channel simulator, I'd pick an idle clicker game. If I wanted a game with huge areas of dead content with a small amount of content, I'd pick Far Cry
Make it more than cosmetics then, if that's going to be an issue - have some unique items that only PVPers can get, which, get this, are ONLY good in PVP (think wow's pvp gear vs pve gear - no person in their sane mind will go into pve content worlds with pvp gear as it only benefits you in pvp.
Keep the cosmetics, pets, construction stuff though, and the thrill of battle with "big fish" being almost guaranteed, because, everyone in that world, get this, WANTS to fight. They're THERE to fight, they're fully kitted up, they're ready and good to go to rock your shit, are you?
Nobody is going to be forgiving if you're going out of lumbridge naked, or if you're a max account going out of smithing (why would you be skilling in a pvp world anyway?), you'd BETTER get ready to get your shit kicked in at any point. Game on.