I know Iain and others have done LOTS of good and solid work when it comes to the applications of the pinan/heians and other katas.
Here is a question though. Take a kata like Taikyoku for example. Do you think that it has the more in depth bunkai as the other Pinans, or do you think that it was more stripped down to teach basic principles of movement to beginning students and applications were NOT the factor in creating it?
I have seen some VERY strange applications for some of the moves and it seems to go against common sense. It almost seems like Sigmund Freud's comment is very applicable, "Sometimes a cigar is just a cigar".