While I appreciate everyone’s point of view, I feel that this is argument has a slippery slope. If I understand your point (please correct me if I am wrong), the issue arises when an individual selects an option that negates a possible game balance condition or that boosts an ability significantly for low cost. At this point they should be prepared for a nerf. The slippery slope arises when you try to determine which option deserves a nerf, which ones are legitimate increases to a character’s powers, and what is sufficient investment to allow the game balance alteration. The argument “I know it when I see it” tends to arise in these situations.
My questions for consideration
There are options to get flight which negates dwarf movement penalties. Does this mean that dwarves should be prepared for a nerf when they get the overland flight spell since it removes a game balance impediment? How much investment is sufficient to remove a game balance impediment without it being considered “cheese?”
Some animal companions are significantly stronger than others. Does this mean that a Druid who takes a much stronger companion should be prepared for a nerf? How would it be if apes, cats, etc were all reduced to a single attack?
Why is the kung fu style to allow charging thru allies shady when used for an animal companion but not when used for a pc? Why is that choice (which requires investing in a feat chain) more problematic than other chains which allow for greatly enhanced attacks?
Mounted feats such as wheeling charge eliminate some game balance conditions in the standard cavalier by allowing turns etc. Should cavaliers be prepared for a nerf? Why is it ok to take a set of feats that allow a cavalier to charge around a corner while other options are problematic?
Why is boosting your channeling via a feat or magic item ok while boosting it thru a FCB is not? Is it because FCB is considered a minor non-typed class ability for all characters (because every character gets FCB as an additional ability to whichever class they select as favored)
My position
I am of the position that if the game designers change something, then a liberal rebuild should be allowed. I would not expect grandfathering but I do expect the ability to effectively compensate for the change. If I make the decision to buy a family of funds and the funds change yielding lower returns, I would not be content to only pick from the new funds. I would want to be able to choose a whole new family of fund since the basis for the initial choice changed. Remember, the choice for the PC was not done based upon a shady interpretation but upon clearly defined rules.