People seem to be looking for excuses not to buy it!
There will be future firmware updates enabling new features. It will be just as easy to import new settings. Any new GoPro isn't going to be that different in size or weight and shouldn't be difficult to recalibrate. It may require a modified mount.
I think the warning about adding filters may be a disclaimer, we will have to wait and see.
I use a GoPro 3 and this is the Gimbal for me. It would be nice to be able to swap over to my Hero 2's or even my drifts but you can only mount one at a time and the Hero 3 Black is the best out there at the moment IMHO.
There is a weight limit for a Phantom and any additions from standard affect flight time. There is choice out there now, some not so good, so go with what you feel is best for you.
There comes a point when what you desire exceeds the limitations of the Phantom and something bigger may be the route to go.