Several threads posted on these forums expose the idea (mostly justified) that the Alliance is lacking story developpement. I believe that one of the problem is that we do not see a lot of real interractions between the leaders. So I thought "What if the Alliance leaders were a Five-Man Band?" It could help to define the relationships between each leaders and help create stories for the Alliance.
To those not acquainted to this concept, a Five-Man Band is a trope from Tvtropes. In a Five-Man Band, you have the Hero(Leader) the Lancer, the Big Guy, the Smart Guy and the Chick. Other roles can be graphted after. Now, here is how the Alliance could be a Five-Man Band :
The Leader : Obviously Varian, as High King of the Alliance. Nothing much more to say.
The Lancer : The Lancer is the band member who, although loyal to the Leader, often contests his decisions. He is also the opposite of the Leader. If the Leader is reckless, the Lancer will be prudent. If the Leader fights with a sword, it will fight with a ranged weapon. It is often the second in command.
In that role, I would see Tyrande. As the main Alliance presence in Kalimdor, the Night Elves are the second most important race in the Alliance. Tyrande may think Varian is not doing enough to reclaim Alliance lands in Kalimdor. She may contest some decisions, thinking that as a native, she knows better than Varian what should be done in Kalimdor. In WCIII, Tyrande was judgemental and reckless. We've seen in 5.2 that she was berating Varian for not being fast and decisive enough. Of course, she acknowledge her error, but one cannot change that quickly... So she could be, if Bliz wanted, the opposite to the new more level-headed and prudent Varian.
One other possibility would be Moira, but her actions would be tempered by the other two dwarven leaders. Jaina could fit now, but she is not a racial leader.
The Big Guy : The Big Guy is the strong arms of the team. Always loyal to the Leader, often friend with the Smart Guy. His sole purpose in the band is as a fighter. He may not be the best fighter, but it's the one thing he's good at.
In that role, I would see the Council of Three Hammer. The dwarves are not the leaders of the groups, they are not the brains either. Their main strength lies in their "brute" force, with their steam tanks and mortar teams. Of course, that role could change, depending on what will become of Moira. Also, the ribald dwarves with their fondness for beer could fit with a category of the Big Guy : the Boisterous Bruiser.
Genn Greymane and his Worgen could also fit in the Big Guy trope.
The Smart Guy : The Smart Guy is either the team's nerd or the cunning man, the guy who is street smart and knows how to get out of any nasty situation. Generally small and weaker. He is often a friend of the Big Guy.
Hightinker Mekkatorque, of course, would fit well. We should see him more often when technology and science is involved (instead of Brann Bronzebeard, even if I like that character). Gnomes are long time allies of the dwarves, so Smart Guy Mekkatorque should be seen often when the Big Guys of the Council of Three Hammers are involved. A special friendship between Mekkatorque and one of the Council members could be interesting. Especially if it's Moira... It would be more classical if it was Muradin. Falstad is more the countryboy type, so it would be a nive contrast with the nerdy Mekkatorque.
The Chick : As the name implies, the Chick is usually a woman. It's the conscience, the heart of the group, the one who brings out balance in the team, who helps the others look at the big picture.
Now, I have already taken Tyrande so that leaves Aysa Cloudsinger. Tushui philosophy could fit well with role of the Chick. However, let's face it, the Pandaren are not a big faction in the Alliance. Also, I think we have seen enough pandaren this expansion. I think Velen, although not a woman, fits also very well in that trope, bringing wisdom and balance in the Alliance actions. I can see him trying to temper Tyrande, if Bliz finally decides to give her back her spine... There is also this Army of the Light thing.
The Sixth Ranger : A late addition to the group, the Sixth Ranger is a former loner, one who was in the fringe of the action, confronting the heroic teams and the vilains alike. He could be seen as a second Lancer in the group.
Genn Greymane could be the Sixth Ranger of the Alliance. He could also serve as a Lancer to Varian. After all, he was pretty much Terenas' Lancer for the whole Second War...
Of course, how these different characters would react depends of the plot that could be given to the Alliance in the next expansion.
So, how would you see that played out?