Agree with OP. It seems like alts are always stuck playing catch-up, but never actually catch up. It's sad and I really wish they moved away from this model. The upgrade system for gear made it even worse =(
Also, even if you are leveling in instances (which if memory serves was proven to be vastly inefficient in MoP compared to questing, plus you miss out on all the rep), it would not add any additional time to my estimate. You would just have to do the Shado-pan and Klaxxi dailies as well. But they can all be done inside the same time frame.
---------- Post added 2013-01-05 at 02:08 PM ----------
All this complaining is simply further proof that Blizzard could send each and every player a real-life wish-granting flying unicorn carrying a solid gold plate of chocolate chip cookies wrapped in hundred dollar bills, and someone would whine that Blizzard sucks for not letting them choose oatmeal raisin.
Do you know how I fixed that? I simply didn't do them.
I also don't have the time to raid heroics or be in a highrated arena-team, so I don't do it.
If you don't have the time for stuff, than you shouldn't expect the rewards for it.
All reps should be account wide, not jut MOP.
If blizzard is going the route that you shouldn't be penalized for playing alts, this is the next logical step.