I'll go out on a limb here and say up front that I haven't the ability
to diagnose your problem over the internet.
I have several of these guys, and while they are nice riders, I wouldn't
get too bent out of shape about having a few parts replaced in terms
of collector value, because, like me, you seem to want to ride it.
If there's a resistance problem in the hub, you ought to be able to feel
it when you spin the wheel with it removed from the bike with each end
of the axle in your hands. Otherwise, given that these guys thought
so little of you that they replaced a QR axle with a solid one tells me
(and you) a couple of things.
1. Their expertise seems, at least in this instance, lacking.
2. You have correctly surmised that possibly the new axle
cones, possibly the bearings, might not mesh with the hub cups
in your wheel. Again, hard to diagnose over the interwebz.
3.Anything is possible, including too many, or too few bearings
in the hub, incorrect adjustment for end play, maybe even
incorrect spacing on the new axle which is leading to some
sort of interference with the stays or drops.
4. You can measure the rear drop spacing with a caliper yourself.
Likewise, someone who has a clue about wrenching should be
able to do likewise. Again, my impression is that you have been
less than well served, and I'd politely, but firmly, point that out
to someone at the management level in the organization...preferably
the owner. If that does not help, find another mechanic, but do
your homework first.
5. I have a tendency to adjust headsets pretty tightly, myself,
so that particular issue may not be one. Sorry for your bad experience,
but this does not seem to be an unusual case in today's world.
