I'm a little confused about how character advancement is supposed to work in Marvel Heroic. The core philosophy is that heroes are meant to start powerful and stay about the same power level throughout their careers. Instead of getting harder, better, faster, stronger, they're just supposed to change (e.g. when Spidey gets the Venom symbiote). How do we do this?
What Watcher resources are there to make sure this "Sideways Advancement" occurs?
The book suggests that players are meant to pick up a new Datafile each Event, and plenty of Unlockables are provided to divert XP expenditures away from Power Upgrades so that "Wolverine can't eventually go toe-to-toe with Galactus". And yet, players can spend 10XP (the same amount as a Major Unlockable, which I feel most players would forego in favor of a permanent Upgrade) to Upgrade a Power one die step.
Given the granularity of this change, and the likelihood of hitting at least one 10XP Milestone each event (not to mention the various other sources of XP), unless there is some trimming back of character abilities, the "Wolverine Vs. Galactus mano y mano" situation is bound to occur.
What am I missing? Are Upgrades only temporary, like Unlockables? Does the game only work if we rewrite Wolverine each Event with a new Datafile, from scratch? To my thinking, it doesn't even make sense that a character like Black Widow would ever even be able to advance her Reflexes or Strength past Enhanced (d8). It just isn't in her wheelhouse.