I love having things account-wide, and I would want even more to be account-wide. Gives me a lot more freedom of choice when it comes to what character I play which is great.
Hell yeah. The only thing I don't like is, that faction mounts like mechano hog aren't account-wide, but faction-wide only.
An awesome feature. Can't really see anyone reasonable being against such a feature.
"Kick in their face with your fist" -phlover
What mounts AREN'T you seeing? All should show up no matter what toons you are on, with obvious exclusions as b0sanac stated. HToC mounts won't be because they were tied to that raid instance and specific heroic achievement, and is tied directly to the character you achieved it on - it would change if you faction changed that character alone, but not otherwise. As Blizzard has stated numerous times, not all mounts are intended to be shared. That's not a matter of "half-assed" it's a matter of certain mounts have different requirements.
It gives a much bigger sense of freedom. I hope that account wide reputation is next on the list ... because that is one thing I really can't see myself wanting to do on alts too, even with 100% rep boost once your main gets revered...
With the new patch, you the mounts do in fact find the equivalent as now the winterspring tiger turns into the venomhide, and the grand mammoth is also available for both factions.
I absolutely love this idea more than anything else. It should've been done in Cata.