There's a problem with that, focused training, you couldn't, for example, grow magic trees. (if you had quest points, you could grow 2). And besides that, the current limit is 3k (30k) in 15 minute period, which would mean 16 hours per day (it could be more, I don't know much they play a day) sweatshop player could get 192k exp per day to a skill, 1920k if 200+ quest points... And if they did that. No matter if the limit is 3k (30k) a day or 15 minutes, they'd lose too many players, they won't do that.