IMHO choices in PlaneShift must have benefits and penalties or there is no point in choosing
In many role playing games, many game masters like this idea of keeping a balance and preventing players from being too strong by the rule "never gives something for free".
But you should not forgot that you're not giving something for free if the players have the feeling that they are progressing when they spend a lot of times playing the game. They've already paid a price. The time they've spent in the game.
In many situations, balancing benefits and penalties does not make sense. While should you be penalized if you've chosen that your character will train a lot hunting ? Does that make you more stupid ? Weak ? I doubt it. Enforcing this type of rule in every situation will be very artificial.
However, I agree that this rule might be good in certain situations. For instance, it is a nice way at the time of the creation of your character to introduce since it might give a lot of varieties in the abilities of the characters. And clearly, it also make sense if you want to give the feeling that the DR should be avoided, not by everyone but by most people.
However, you should be very careful how you would introduce this into the game. You might actually break the balance unless you are very careful with the implementation.
If certain characteristics can only be mastered in the DR, and if you penalize everyone who decide to try to get them, then it might look very unfair, given the fact that all the other characteristics can be trained without any problems in the real world. Thus, to keep a balance, what you could get in the DR should be special. They are no reason to penalize someone who just want to learn a spell which does not have any strong effect, and does not lead to anything special, just for the sake of penalizing people.
You could even say that no real character would sacrifice anything important to gain something not important. Thus, you'll have to work very hard on the balance. What you could gain in the DR should be special, not just get trained by a master of another way, which apart from the name, is close to any other ways. But of course, it should be hard to get, and you should pay a heavy price etc...
Good luck.