Because in those games they can see it coming from a mile away. You’re bound to a single screen in isometric view ARPGs. If there’s a really strong player a screen away with high effective range spells, you’re a sitting duck unless you’ve made aware of its presence before hand. You can not be this dumb to not understand the situation. Question is simple, is it an active buff once for ready or you have to do something else once it’s active?
You’re contradicting yourself and shrugging the question. How can you get untouched if you past by someone with it active? If that’s the case how is it any different than sending a chat message “looking for duel” to all channel?
Why not then? Designated grounds can offer you a way of curbing such overpowering skills and allow map generation in a pattern for creating hazards around the area. Even if you have the best gear, your chosen skill may fizzle in those PvP grounds (because it’s overpowered in PvP duels) and you can get lured or pinned down to environmental hazards for an instant kill. This sounds balanced to me. It all has to do with map generation because genre has shortcomings for player control unlike your examples.
Do everyone a favor and play legacy D2 PvP or at least read about its balance. You keep giving examples about how Dark Souls is an amazing game which is a whole another subgenre.