Thank you for the response.
More specifics? Hmmm... Where do I begin?
Our group only gets together to play about once every 4 to 8 weeks. This past weekend, when we were playing, we were experimenting with a house-rule that expanded the "Disabled" stage as it concerns hit points to an amount equal to the character's fortitude bonus. One player made the comment that he didn't think that every fighter would necessarily have a good fortitude progression. So, that got me thinking "What would be the harm in allowing save progressions to be traded?"
Now, having the Disabled stage become based on fortitude strengthens the value of fortitude considerably, but he was wanting the option to give up the good fortitude to take either a good reflex or will progression, instead.
As a counterbalance, we're using a house-ruled variant of the Base Defense Bonus variant presented in
Unearthed Arcana. We have a fairly complex mathmatical formula that takes into account the hit die size, save progressions, and BAB of the class in question in order to calculate which Base Defense Bonus progression a class gets. So, I was thinking that since Reflex might be a little less important with our house-rule mentioned above that makes fortitude more important, it might be a good idea to just use the Reflex progression for the Base Defense Bonus.
In that respect, I could see fighter's with good reflex save progressions (and poor fort and will) becoming more common because Reflex would be tied to AC.
I haven't mentioned any of this thinking to the player in question, but I'm strongly considering it.
What problems do you think it would present if someone was playing a swordsage and traded out one of their save progressions? We aren't using the Bo9S, yet, but I plan on adding it to the available classes sometime in the next year.