Imaro
Legend
But it can ease the need to keep the systems balanced.
The point of the absurd example is that the player has spent points on one skill that some GMs are going to have a hard time figuring out how to challenge enough times to make it mechanically worth the purchase. The idea of balance is to attempt to eliminate any choices that are either costed more than their amount of usefulness would suggest, or are costed less than their amount of usefulness would suggest.
Yet you continue to avoid the question of tactical combat, why? Isn't this the same principle? Balance doesn't help this as it really boils down to creativity and imagination. You can, through bad or good combat design, make a characters powers shine majority of the time or less relevant than other players powers, or barely relevant at all. What about the players who can't or won't be able to learn to create good combat encounters. IMO, it really boils down to the DM
It doesn't hurt to have a backup in case none of that works.
What backup? Limitation of choices for your own good? Eh, I'll pass I can make my own choices thank you very much. See it's all about preferences.
You make the point both here and above that the character should have multiple skills to draw from. Multiple options. But that's one of the things the balance argument is striving for: the idea that any given PC has multiple options they can draw upon so they are not sitting on the sidelines because of their mechanics. Again, the point of the absurd example is that the skill has only application and figuring out how to apply that application enough times to make the skill's purchase worth giving up what other options could be purchased may be beyond some GMs.
No, having multiple options has nothing to do with balance. A game where you can attack, or run with a 50% chance for everyone to do either is balanced... but it doesn't have many options. In fact I would argue that the more options introduced, the less balance can be achieved, since it causes the amount of inherent possibilities for which the foundation of said balance can not account for to rise. As far as it being beyond some DM's... how do these DM's cope with again, the rogue in 4e having twice as many skills as the fighter... so the DM/GM has to create situations in which both of their abilities are useful... or you end up with the Rogue getting more screen time. In the end it really is about the DM/GM not about the balance or mechanics.