This thread intrigued me as I've been playing Noble for quite some time... OK, trying to play noble. Unless I start with some ideal location, I always get my butt kicked.
The bad thing about this game is that it's not obvious where you've gone wrong, so you keep repeating the same mistakes. I often wish for a snarky AI that will pop up and say, "You idiot... what are you thinking!" I've found that I can consistently over-culture the other civs, but forget the rest.
I couldn't have wrote that better myself. I do the same thing awesome culture but everything else in crapper. But I did almost win my first noble game over the holidays. I lost to a space race right before I was to finish mine.
I think you need to look at this and determine what to do differently at higher levels. Perhaps its time to stop going for Stonehenge, and stop building those Culture buildings, and make more troops instead. Stop chasing those early religions, and temples, and work a different tech order. Try using civics to take advantages of the "new" playstyle, like Hereditary Rule, a civic often ignored by newer players, because you dont NEED that happiness at noble or below. I dont think I ever used that civic until I hit Monarch. (for example)
There is also a big "fun" factor. I play Monarch because its an enjoyable few hours. Its hard enough, some games I cant equalize for a LONG time, but the more I play the more "sense" I get about how far behind I really am. On Emperor, I get crushed baddly half the time, and if I adjust to that, I get so far behind in tech and development it seems impossible to catch up. Truth be told, if I tough it out, and grind grind grind, I could likely catch up in the Emperor games, but its just not as much fun "grinding". I enjoy "kinda bumpy but mostly smooth" Monarch.
And remember, its all about adapting. If you say "But I want to play my own style, 100s of cities with all the buildings and a skeleton army (1-2 units per city)" then you arent going to get very far up the difficulty ladder. Once I modified my style to iron out the things I "tend" to do at lower levels, the jumps were easy. (my biggest faults being great culture, solid religion, Stonehenge, and no army, no Pyramid, etc, heh). You seem to have your finger on where you need to make adjustments. You just seem reluctant to make them, and thats fine. But if higher difficulties are your goal, flexibility is pretty key.