Would gladly buy just to play unknown/unknown again without running a high risk of freezing or memory leak (lolpeaesstree)! A new manifest wouldn't bother me much at all, actually would prefer it. Just bring back premium veteran packs!
If there isn't a manifest/challenge wipe please add some more things for current end-game players to do. New challenges and banners (vanilla kits) for example. An option to prestige/reset everything would be nice for returning players who would like some sense of progression again. Maybe give a unique banner or armor customization for doing so. Just something cosmetic, no stat bonuses or anything.