I think your point 1 and point 2 are pretty much the same thing and like I said, I do think they need to change this. It's stupid you can attack someone, become purple named and then that person (you attacked) kills you from AOE on HK after which you can venge them non stop for 2 weeks. This can never be the point of ''venging''
As for point 3. If people currently get venge on you, there is nothing you can do, you can only go to maps or dungeons where you can't get venged (inter, ashkeena, blazing temple) or you can prevent getting venges on you by grinding with MR 24/7. Both options are kinda stupid and aren't real solutions to the problem but rather bandaids to mend it.
What I meant with ''there are enough maps to xp at'' is when they'd actually FIX the system, there is enough space for everyone to play and xp/farm. You could move around and make people search for you 24/7. Like you said, this was the job of rangers. Currently this doesn't go because of the venge system.