[quote=Captain Jordan]
To be fair, AGOT, ACOK and ASOS were written as a trilogy. Clearly, that didn't pan out, as we're sitting here with 5 books out of a planned 7. However, it makes some sense if you consider the first three to be a trilogy reworked into a larger series, they're quite cohesive and fast paced compared to the later books. We can only hope that The Winds of Winter will speed things up.
[/quote]

I'd say most of the slowdown from going from a 3 book series to a 7 book series happened by the second book; book one featured considerably more plot progression than any later books. The main problems with books 4 and 5 is that they are just one book split in to two with a bunch of filler thrown in. Sure, it is possible that what was originally planned as book 4 featured too much content to feasibly fit in one book (#Doubtit), but the way they handled it just wasn't the way to go to keep the series' artistic integrity intact. It made them more moneys, but it added two sub-par books to the series as apposed to one possibly-ok book. I both hope and expect the sixth book to bring the series back to where it should be, but if they try to continue sellout tactics in the last two books the series will likely be ruined for me.