I would prefer it if he decided to start the main story.
So far, all the books written have served only to introduce us to the setting, with a vague hint of "winter is coming". We cannot actually say whether the winter is the main plot line or not.
It's like a soap opera. There's nothing happening, except characters acting and reacting. No one is accelerating the main plot (because we dont know which plot that is).
Tolkien said very early on, "here's a ring, the story will concern its destruction". David Eddings - evil god does bad things, here's a story about his demise.
And when we read those books, we form expectations about what is going to happen, and we start to trust the author when that happens. That's an important connection between author and reader.
Song of ice and fire, well, anything can happen. Hell, the bad guy in book X is the good guy in book X+2. I respect Martin because he can pull it off.
I do, however, not trust him to take sufficient care of the characters I enjoy the most - he's proven he has no qualms about killing them off (or leaving them out entirely from a book), then resurrecting them and making them evil. And then the 3 year cliffhangers...