WoW has had a mixed history with faction reputations, and each expansion has tried to shake things up. Burning Crusade brought us gated grinds with daily quests. Wrath brought us tabards to wear in dungeons. Cataclysm combined the two. Mists drastically changed things by adding dailies, removing tabards, giving rep for a dungeon run per day, and eventually the faction Insignias. Personally I liked the variety approach, the problem is they had to set caps on most of them to avoid people grinding out reputations in a single day due to each giving a relatively big burst. Then we got Warlords where Blizzard transitioned most of the reputations into straight-up grinds with the occasional burst from a follower mission.
To me this feels like a failure and took away the "everything helps" feeling that Mists had. Sure, it had it's flaws but it was much less painful than any grind before. Now Blizzard may improve reputation gains in subsequent patches, but that remains to be seen.
So how do we fix this? I'd take a page out of their Valor point book.
You would split reputation gains into two types which I'll temporarily call Daily and Grindy. You are limited to a finite amount of reputation per day from Daily means and these can include quests, dungeon runs with a tabard (or something similarly wearable), a daily dungeon burst, etc. On the other hand, you can gain as much reputation per day as you want from Grindy means which could include killing mobs, using tokens (insignias, etc), or follower missions.
This solution ensures that people who prefer the gated daily method (aka, logging in for a short period each day to get a large burst) can still do so, while the people who want to grind it out at their own pace can do the same. I can't stand pure grinding, and call me whatever you like but I think adding a burst in the form of a daily helps keep the grind from becoming mind numbing.
To encourage multiple styles of play they could also limit the number of Daily quests under the "Daily" reputation gains to grant less reputation than cap, so that people are still encouraged to run dungeons to cap out per day.
The idea here is an elegant solution, one that satisfies the playstyles and preferences of most players. They could even make offer resource/crafting oriented players the option to donate goods (similar to Ixal beastmen in FFXIV) to gain "Daily" reputation or even for "Grind."