@surreality Absolutely makes sense. On FoH, you also get XP from noms and from events. Goals are intended to be the main way to advance, but not the only way.
Also, you can abandon a goal any time you want, or add one (assuming you aren't at your max already).
I do agree that you have to choose your goals carefully, but the ability to change them at need helps with that somewhat (so does not picking them to depend on specific other players).
To the point @HelloProject and @surreality are talking about, goals could easily be tied to explicit boosts, rather than to XP. Want to improve your character's social skills? Put together a goal where they get elected to the school board--if/when they succeed, they get +1 Bureaucracy and +1 Charisma. Want to improve your character's shooting skills? Put together a goal where they're recognized as one of the best gunfighters in this dusty town--if/when they succeed, they get +1 Pistols.
@faraday has put together a really nice XP-spending system for Ares--you apply XP to skills, and each skill has a cooldown, and when you get enough XP applied to a skill, that skill goes up. As a skill goes up, the amount of XP needed to increase it goes up, so overall learning time goes up too. Yes, it rewards/encourages broad skill bases rather than focused ones, but I generally think that's a good thing. If you didn't want to reward this quite so much, however, you could simply add in a caveat that for double the XP cost, you could halve the learning cooldown. I like the system because you can see XP applied to skills, so you still see progress, even when your skill rating hasn't actually changed.