I'm the weird player that min-maxes her XP, rather than +sheet effectiveness, which is really more an issue with decreasing returns.
I would have no problem with decreasing returns/scaled XP costs, if the chargen itself wasn't linear. You can put all four dots into one skill (making them 30 XP total), or you can spread them across 4 separate skills (making them 12 XP total).
This happens with everything. Everything
Be they attributes, supernatural powers, merits... it is universally cheaper to just buy values at higher ranks. It leaves your character a bit one-sided out of chargen, but it gives them, not only a mechanical benefit to their chosen skill, but also an effective 18 extra XP over people who make something more believable.
In short, I think GMC did the complete wrong decision. Scaling XP costs should have remained, and players should have been given a pile of XP, had their attributes set at 1, their skills set at 0, and had free reign over where their points should be spent.