This trust is no different from trusting that when a good author slows down the pace doing character development halfway through a novel, that he'll appropriately speed things up in the coming pages. The only difference is that those pages haven't been completed yet.
We aren't basing our trust on wishful thinking, but on a solid history of great writing. I would turn around your argument and say: the only reason you're complaining about this is that you think Rich might stupidly keep the pace of the main plot this slow for the rest of the comic, which is blind pessimism rather than rational criticism.
On a side note, ASoIaF might be a sprawling epic, but over the last couple of books it has sprawled flat on its face, lost all sense of pacing, and thrown in a few too many "evil people having gratuitous deviant sex" (connotations of "it's baaaaad because evil people are doing it") for my liking on top of everything else.