Not at all against choosing to roll the original stat as a fix for an individual game group, but I want to point out that the printed text does not say "you may use cool instead of hard" (or whatever), but "you use cool instead of hard." If rolling the original when the fiction demands is a necessary fix, then it should go in the text next time revisions happen.
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I also don't completely accept Vincent's assertion that it's not the MC's job to worry about how fast characters earn XP. If I understand him correctly, the assertion is that since failure is as interesting as success, having a "more powerful" character does not make the game more fun, and in any case different characters have such wildly different competencies that discrepancies in the number of avdances aren't really noticeable. (Is a Hocus going to be jealous of the Gunlugger because he has more advances? No, they're each doing their own thing.)
I'd agree that in a game where player's don't regularly go all out on each other, they all have their own schticks, and there's a little maturity, trying to keep the party "balanced" in the way you would when playing D&D or something isn't really necessary. But there's a bigger problem with advancement: it undermines the premise of the game.
The Character Creation session does a lot of setting the tone for the game to come, and which playbooks are chosen can be very important in that regard. If nobody takes one of the Leadership playbooks--say you have a Driver, a Gunlugger, and a Brainer--then often the PCs will end up a little less attached. The game can be more mobile and "pulling up stakes and leaving" is a viable respons eot some problems. On the other hand, with a Hocus, Chopper, or *especially* a Hardholder, the story is naturally going to end up revolving around the social groups the Character have created. Most of the game reports on this site revolve around the troubles of a PC Hardholder's holding.
Well, almost every character has the option to pick up a holding or some followers as an advancement, and the faster the advances come, the more likely you are to see that. Unfortunately, adding a new holding has a major effect on the entire game, not just that player. The overall mood can change, lots of new NPCs may need to be invented, and existing threats may need to change shape to remain relevant. The same effect can happen with certain more prosaic moves, too. Picking up "not to be fucked with" can make formerly scary raiders much more manageable.
The bottom line is, the faster advancement happens, the harder it is to predict the outcome of events, the faster existing threats will get churned through, the more of the MC's prep time will be wasted, and the more work will be required to keep up with the advancing story. Keeping the reigns on that is absolutely the MC's perogative.