Bulwinkl, you've got a real kindred spirit here!
I haven't been here in the forum for quite awhile, or I would've immediately replied, because I had even posted my own complaint about this very same issue earlier on this forum! (and I continue to be surprised that we sufferers apparently are in such a minority....)
I am a 5'3" woman, so obviously not a big head size. I immediately found the driver's headrest intolerable, and thus a MAJOR problem. Like you, it forces my head way too far forward and down, making even a few minutes' drive uncomfortable and then painful. Apparently choosing to have the seat back in a very upright position -- like you, I sit with back and head upright, like I do when walking -- results in the forward/downward backrest. Guys at the dealership laughed and said that some people like to put the seat so far back that some of them even drive with their knees since their hands won't reach the steering wheel; obviously for them the backrest would be ok.
As soon as I drove my new Mazda 5 home, I immediately ached--literally--for the headrest in the '87 Camry I was giving up: those headrests ratchet front to back. Mazda could simply have made these headrests, at least in the front row, similarly adjustable both up/down AND front/back, and that would have, I'm sure, totally resolved the problem. (This was one of my complaints in my response to the "new owners survey" sticky thread, btw, along with wishing for more/better overall seat adjustments: I really had to mess around with the levers and pumps to FINALLY come up with ONE decent combination for my body and driving style).
The upshot, after talking with Mazda parts people, going to auto supply stores, etc., and being told there was nothing, was to simply turn the driver's headrest backwards. Yes, it does fit in just fine, tho without the up/down notches working; but I leave it down, so that's ok with me.
In this backward position, tho, it's actually a little bit too far back for me, but not pain-inducing as the normal position is. I'm still thinking about finding (or making) some sort of additional little pillow or bean bag to hang over the top of the headrest that would bring my head just a tiny bit more forward, and that would be just right.
Thanks, 07MZ5SA, for the details on a better fix. Still too involved for me to run out and do, but I'll remember this in case I decide to go that route.
Have I increased my chance of whiplash? Dunno, but I've saved the ONGOING cost of chiropractor appointments I would've faced if I hadn't turned that darned headrest around!
Hope you've found a workable solution for yourself by this time, but maybe someone else will check this older thread for the same reason.
Cheers