It always feels a bit anticlimactic and pointless to have your whole world progress wiped without anything to show for it.
In path of exile, after each league you get a totem for your hideout which visually represents how many challenges you completed that league. Then you can line up all your totems and show off how you completed every league.
It'd be great if there was any way at all to show off your progress from previous worlds in Haven. Whether its a cosmetic item you take out of your HF or a forum badge or anything. Stuff like that goes a long way in keeping people motivated to keep playing and not just thinking "well its all gonna be wiped anyway theres no point continuing to grind". You could have medal tiers for being top 0.1%, top 1%, top 10% of players etc. Maybe there could be an item you build in game which shows off your past characters/achievements. Like the thing you can build in your runescape house to flex to the public.