[kstrauser]

If the headphone jack rumors are true, I'd bet it has nothing to do with audio quality and is more about the limited usefulness of the old jack. It plays music fine, but has no support for microphones or controls (like the fast forward / pause button on Apple earbuds) without weird nonstandard hacks (like the extra ring on the jack of Apple earbuds).

[sjwright]

If the headphone jack rumors are true, it will come down to reclaiming space inside the phone and possibly also waterproofing.

As long as Apple ships a small adapter with the phone, I have no problem with it.