To each their own, second time around with Mad Men tends to try my patience, second time around with Game of Thrones was enriching & brought more of an understanding of just what they had accomplished. It doesn't hurt that there are at least a few characters you can actually like in Game of Thrones.
I'm kind of fickle in what impresses me more, in that I really appreciate small, authentic drama (which is why I love Friday Night Lights so much), but I'm also won over by sheer audacious ambition when it's brought to successful fruition. It's true this show is so big that it's characters do not get as much of a chance to develop as smaller shows, but that all the moving parts work & involve you into the conniving politics of a made up place so much, that's impressive. Though it helps in cases like LOTR & this that the fantasy is a hook to hang relatable struggles, emotion & allegory for me to care versus just straight up crazy fantasy that's completely removed from real life.
In terms of scale, from what we've seen, season 2 looks like it'll make Rome seem low-rent.