I do agree that the realism/grittiness of the series is overstated. Robbs Death flowed naturally, but now I do think he's just killing off the Lannisters and Freys for the sake of it. The Stark kids are pretty safe whatever they are doing, so you got a point there.
I don't think Magic is too prevalent. It is clear from the Prologue that there is some Magic aspect, the key to its success is though that it's not the Magic of TVtropes.com . It's no Deus ex machina but something that has too be earned and can go horribly wrong. Everything has its price and so on (although it remains to be seen what he does with Bran though).
Wether GRRM is just expanding ever more without coming to a finish anytime or wether he does have a plan is impossible to say for us outsiders. It looks like he had a big problem in the middle of the series, with AFFC, ADWD and (probably) the first part of TWOW. It took him more than ten years to write them and he did start the Dunk&Egg-Stories in the meantime as another side project for the Westeros world. But if he is right, he now has solved the Meerenes Knot, and that remains to be seen...
EDIT: Why I don't think there's too much Magic:
- The Others have been introduced in the Prologue of the first book. They have been talked about plenty in Brans Chapters f.e. (Old Nan). They are the magical arch-enemy of the series. Something it does need somehow, not'
- The Wights (Walking corpses) are in connection to them. They are what makes you fear the White Walkers especially. They are why Jon is trying to get the Wildlings South of the Wall. So they do have a plot point merit.
- The Dragons are the plot point for bringing Dany into the Plot. Without them, she would have been brought back to Vaes Dothrak or ended up again as the beggar queen and a sideplot to Illyrio. So, they do have a plot merit. Also they are fun. What fantasy series without Dragons? But they're no deus ex machina, as they are incredibly hard to control, etc.
- The Ressurections of Beric Dondarrion, Catelyn and others by Red Priest. They do introduce us into the more Fire aspect of the Song of Ice and Fire. They are mostly world building, I do agree. Dragonglass candles and shadowbabies are well pushing it.
- Qyburns Frankenstein's Monster and so on, yes, it seems to much...
- Warging generally is seen as a character development point for the young kids and it discusses ethical questions (Bran going into Hodor and Hodor retreating). Also Bran is maybe set up as a all-knowing entity, but limited in power. The Watcher in the Dark. Also not Magic for the sake of Magic.
- Ironborn Magic is probably not Magic at all, just superstition.
- As for the Queen of Slaves, that's nothing to do with Magic but is a character trait of Dany and has been part of her arc the whole time. (not being able to move freely in her childhood, Jorah telling her of how he ended up in exile, the incident that got Drogo killed...) It was Viserys dream to become King, she just somehow rolled with it. Otherwise she would have just moved further on much sooner.