I'm generally 100% okay with 4e's retraining. Hell, in 3e I let people rewrite their character sheets any time they wanted as long as they didn't do anything stupid or do it all the time, just as long as they kept playing the same character in a story sense. This is because these games have a lot of complicated options that you might find you really want later. Or you might take something frickin' stupid and not want it any more.
I've only ever had two problems with retraining - one is that some people can be kinda twits about it, especially if they think they know what's coming up beforehand ("Hey let's all retrain to trained in mountain-climbing for this one adventure! "), and... well, 4e D&D is still a traditional roleplaying game with a game master and everything, not an MMORPG. If it's stupid and making people have less fun, your friends or your GM have the right to tell you to quit it.
The other is if you can retrain more frequently (or more deeply) than 4e allows, like in Guild Wars, there's literally no difference between any two characters of the same class and level. In Guild Wars, for instance, stepping into town for 30 seconds is long enough for me to completely swap my character's entire build for another because it's more effective for what I'm doing next.
I've only ever had two problems with retraining - one is that some people can be kinda twits about it, especially if they think they know what's coming up beforehand ("Hey let's all retrain to trained in mountain-climbing for this one adventure! "), and... well, 4e D&D is still a traditional roleplaying game with a game master and everything, not an MMORPG. If it's stupid and making people have less fun, your friends or your GM have the right to tell you to quit it.
The other is if you can retrain more frequently (or more deeply) than 4e allows, like in Guild Wars, there's literally no difference between any two characters of the same class and level. In Guild Wars, for instance, stepping into town for 30 seconds is long enough for me to completely swap my character's entire build for another because it's more effective for what I'm doing next.