All RPGs have a shelf life of when characters become so competent they are nigh on impossible to challenge and become not terribly interesting to play. This is hardly the first game to experience that syndrome. If you hand wave more xp to begin with, you bring that time on sooner.
One solution to this would be to allow higher XP to start but to reduce the typical XP awards. This allows for front-loaded characters with the skills and talents that players really want for their concept and then slow growth/development from there. This fits with many books and movies where we see characters that are already rather experienced but don't show the rapid growth spurts we typically see with RPG characters. Some players will prefer this style while others like the one in the book better. It's a matter of taste.
Ooh, I really like this, actually. Maybe not for the next campaign, but probably the one after. Thanks for suggesting it!