As I posted elsewhere, I'd rather pay a little bit more and have the chance to get all the Doctors on my shelf one day, than pay less and be practically guaranteed to have significant gaps in the collection.
I really do hope they manage to shift all these Hartnells. After all, 500 is still a lot for a niche line of classic series Doctors, within the niche that already is Who high end collectibles (Who has never done very well on the high end collectibles market). I can see Pertwee shifting 500, the rest of the classic series Doctors, they seem less likely to do so. Still, hope I'm wrong, but I certainly wouldn't be surprised to see future lowering adjustments made to the total runs of other classic Doctors.
Hopefully, they'll find the happy medium of sales and edition size, and every Doctor will still be profitable enough to be worth doing, whatever their total edition size may be.