While on it's own it may not be enough for some to warrant a purchase (which is perfectly understandable), it makes sense that it would be one of the first features mentioned for 15. The ability to continue a franchise/career from one iteration to the next is a hugely important accomplishment for the sports genre and, as others have mentioned, this is the first it will be seen in action..
Now, personally, I certainly want more features than save transfers if I'm to purchase (after all, there needs to be a compelling reason for me to jump ahead), but I don't think SCEA can tout the feature enough.
In any case, it's December. It's far too early in the information cycle for me to be too up or down on anything related to 15.
This is kind of where I'm at with it. I actually have no plans of transferring my 14 franchise to 15 because of stat tracking. If SCEA finally updates year-to-year stat tracking (God, I hope this is in for 15), then I don't see a way for such info to be generated from seasons completed prior to their inclusion, which would mess with career numbers (for CAPs in particular) in certain categories.
We'll see, I guess.