1. Free Mode, AKA chapter select AKA replay any Chapter or paralogue with any sets of characters, like in Warriors games.
2. More NG+ options, like get relic weapons by spending renown, "unlock" route locked chars to use in any route, option to unlock classes to use without getting req Lv or skiil Lv.
3. Some QOL like remember the adjuntans positons, stat busters use from convoy, BGM select in all missions and not just free battles, more save slots.
And yeah paired ending select would be nice.