I hate them when they essentially become mandatory.
Yes yes, free will and all that.... I know, heard it before. However, if Blizzard had toned down/capped Tabard Rep, but still left it as an option it would have been a far better system.
Anytime they essentially bottleneck us into one route, it's a horrible design flaw. Dailies aren't "mandatory" but they're the only way to earn rep with the MOP factions if you want their mounts/recipes etc. Don't care about vanity items? Well you still need to do dailies, because while you can farm valor in group content, you can't spend it on anything without rep, which requires dailies.
Bit of a rant here, but I'm sure people get my point. They went from one flawed system (everything behind Tabard rep) to another flawed system (everything behind dailies).