Yeah, I think GoT S1 is quite possibly the best season of that show. But the whole thing has been strong.
I think it's ground-breaking. It has LOTR-level epicness and world-building, but on television, and I don't think that's ever been done before. Feel free to correct me if I'm wrong.
You say it's a "gimmick" show and then list reasons. But if the things you listed are it's gimmick, then that means it's gimmick is a high level of quality.
The show is so rich on every level.
My point is it's a gimmick, but that doesn't make it as great as people say it is. That said, I've only seen a few seasons... So I can only comment on that. But from what I could tell in the beginning, I felt there were way too many characters, which made me hard to care about any of them, hard to follow the story, and barely any actual plot development occurring. It had it's moments, but to me, slow moving story arcs work much better with much less characters. There's just so much going on, I feel it took time to get the foundations in place.
I think it's gimmick-ness, sexual/nudity, epic scale and production value mask some of the flaws of the show.
I prefer Dexter season 1's character driven story. It's much more grounded and the beauty is in it's simplicity. It's not overloaded with things happening, it just tells a deeply psychological story from the mind and perspective of a very interesting character.
Note, this is all in the beginning when Dexter was at it's best and original.
Not to say monologue driven character stories haven't been done before, but Dexter as far as format and style, stands out from the rest. Gimmicky, but it's subtle and doesn't have to mask any flaws in story telling.