I personally look at the end game grind now and think "oh, f**k that". It was fine when I had one main, and even enjoyable back in BC. But now? with 10 toons I have levelled? I look at them and think, "meh, sod it", and instead find myself turning WoW off.
Thats why they alts, u dont have to do it, heck u dont have to do it on ur main at all.
And if u wanna do it, wait till 5.1 it goes quicker and if u VP capped on ur main (which is easy to do according to a hunter in my guild as i havent been capped even since MoP).
She does Dailies before server maintainment, doesn't turn them in but log out @ quest givers. Logs in next morning when servers back online and turn in the quests. She still have the increased VP buff from being VP Capped from pre-server reset which goes away after u log to different char. Its minor increase but still an increase in getting VP capped again. Do the first day 5-man bonus + lfr and she is nearly capped on the first day so her alts getting the buff on day 2 after reset and her alts are always VP capped within the half of the time spend on her main by just doing daily 5-man and LFR.
Just saying, doesnt have to be a long grind (specially now that all LFR has opened) as for rep just wait till 5.1.
Have 14 toons.. 4 at 90, (monk, Warlock, Hunter and warrior) and several at 86-87 the rest are 85... I stopped playing recently as I just didn't like the feel of any of the classes I've tried since the changes... I refuse to level all my toons to 90 just to find a new main. I used to love levelling (hence so many toons) but the levelling in Mop is definatley a chore.