I really like some of the story direction elements that go into unlockables in Marvel Heroic events. I like that it shows XP aren't just used for the traditional RPG convention of lengthening and broadening the abilities of a character.
That being said, the Basic Game gives an awful lot of examples that line up with more traditional XP expenditures. It makes perfect sense, because a lot of unlockable XP expenditures are very specific to the events in which they appear. Unfortunately, if you add traditional RPG mindset to the majority of examples being in that vein, it's understandable that some players might feel as if they should be using their XP to boost their traits, add powersets, get more specializations, or pump up existing specializations.
Also, what works for a specific event may not work as well for a game that is more loosely organized into "story arcs" as much as acts, and might need some broader story based goals.
With all of that in mind, I threw together some ideas about what kind of unlockable XP expenditures might reward the player that doesn't want to change their hero's stats so much as they just want their hero to sink his teeth into the plot a bit deeper.
Asking for a Favor
For 15 XP, a hero can call in a favor to end one scene favorably in a manner similar to the Watcher ending a scene by paying 2d12 from the Doom Pool. The Watcher should warn the player if they are nearing the end of the act, and should work with the player to avoid ending the act in this manner.
The player should explain what kind of favor he is calling in, and from whom he is calling in the favor. This favor should be tied to one of their specializations. A character that is a Grandmaster in the specialization tied to his favor gains a d8 complication, a character with Mastery in a specialization tied to the gains a d10 complication, and a character with an Expert specialization gains a d12 complication.
This complication can be removed by acting against in during a Transition Scene. The character assembles a die pool opposed by the Doom Pool and the complication. If the roll is successful, compare the effect die to the complication. If the effect die is equal or larger than the complication, the hero has fulfilled his side of the bargain or been released from any obligation. If the effect dice is smaller than the complication, it steps down. The Player should explain how he is working to pay back his favor and assemble his die pool based on this description.
The complication steps down each time the event moves to a new act. It is assumed that the hero can do some work behind the scenes to pay back this obligation a little bit at a time, even if he doesn't spend a Transition Scene to work on this obligation. A character cannot ask for another favor in this manner until they eliminate the complication from another favor.
For 15 XP, a hero can declare that he is working on a backup plan. The hero can end an action scene in a manner similar to the Watcher ending a scene by paying 2d12. A hero can only come up with one Backup Plan per act. Whenever a character sets a Backup Plan in motion, he describes how the plan resolves the scene, and then adds a die to the Doom Pool.
The Backup Plan is tied to one of the hero's specialties. A character with a Backup Plan based on an Expert Specialty adds a d12 to the Doom Pool. A character with a Backup Plan based on a Master specialty adds a d10 to the Doom Pool. A character with a Grand Master speciality tied to their Backup Plan adds a d8 to the Doom Pool.
A player may spend XP to call in a Guest Star for a scene. The Guest Star is not fully detailed, but is represented by a die type. It costs 10 XP to call in a d12 Guest Star, and 5 XP to call in a d10 Guest Star. The player and Watcher should work together to determine a hero that is a good fit for either designation.
The Watcher controls the Guest Star, but the Guest Star will always act in favor of the hero whose player paid for their appearance. The Guest Star has their own spot in the regular turn, and on that turn, they can do one of the following things:
Create an asset equal to their die rating.
Add a complication to an opposing character.
Add stress to an opposing character.
Remove or step down an existing complication.
When acting against another Watcher character to add stress or a complication, the Guest Star compares their die rating to a relevant trait of the other Watcher character. If the relevant trait is equal to or greater than the Guest Star rating, the stress or complication is stepped down. If the Guest Star rating is higher than the comparison trait, the stress or complication takes effect at the full die value of the Guest Star.
When removing an existing complication, compare the die rating of the Guest Star to the complication. If it is equal or greater than the complication, the complication is removed. If the complication is greater than the Guest Star die rating, it is stepped down.
A Guest Star can take stress and complications, but these are only used to determine whether they can participate in a scene. A d10 Guest Star is stressed out or complicated out of a scene if they take a d12 stress or complication. A d12 Guest Star is stressed out or complicated out if their stress or complication is stepped up beyond d12.