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 =(
I had a feeling you would mention the achievements. I don't think we would be having this conversation if account-wide achievements had not been put in. Now that Blizzard did that, I see people everywhere asking for more and more things to be account wide. At some point you have to accept that you must actually play these characters if you want more than one.
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 ----------
So don't do all of them every day. Pick one faction. Work on that one only. If you do just one faction's dailies every other day, you unlock gear faster than you can earn the Valor to buy it. And it would only take you 30 minutes at most, every other day. 2 hour, every day, for 2 weeks is just the quickest possible way you can get them done. There is no advantage to doing them that fast though.
I found I enjoyed the game significantly more when I stopped paying attention to all the people on the forums telling me how much I am supposed to hate itAll 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.
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.