I had a revelation while playing Mass Effect 2 the other day and I now know what Mass Effect 3 will be like. It's going to be all about recruiting Factions of people to help your cause.
If you saved the council in the first game then that helps you recruit Turians, Asari and Salarians. If you saved Wrex then that helps you get Krogans. If you saved the Rachni queen then they will help you. If you convince the Quarians not to go to war then they will help and if you reprogram the Geth then they will help. Maybe even people like Aria help you depending of what you did for her. And don't leave out the Shadow Broker whos connections to Liara could be interesting.
I am proud to say I have reached the ultimate nerd level and have cracked the mysteries of Mass Effect 3