Looking back now, it reminds me a bit of Lost, in that it had a great premise, superb first few seasons, great characters, then quickly got too samey, daft and drawn out. If it'd been 4 dynamite seasons, 5 at a push, it'd have been one of the all-time great shows. But the last 3 seasons are nowhere near the quality of what came before, and it's stock has fallen substantially
I'm predicting the spin off will die on it's arse, too. It's had it's moment
EDIT - Oh, and I too would love to see the White Walkers win. As humans are cunts