You're the one chasing unicorns fella.
Multiplayer expansions tend to add OP equipment or buffs as part of the new content. It's one of the motivations to buy it. (Plus adding new game mechanics that don't provide new gameplay variety and advantages would be both very difficult, and ultimately pretty self defeating). A purely narrative game could add content chapters or whatever. A multiplayer game featuring PvP, and indeed PvE, tends to add new weaponary / vehicles etc which are both functionally diverse and better in key respects than many of the prior set. Got any examples of recent, comparable games that
haven't followed that route? I kinda doubt it
You are being deeply unrealistic mate. But enjoy the unicorn hunt