Shock value does not really age well. The entire series would have still been equally interesting (more so, I could argue, especially for revisiting), if it actually tried to "play it straight" and not just write off major characters early on. Martin somewhat understands that he has to actually make something out of those kills and try to introduce "replacement characters" that will carry the story, but knowing a lot of the things that we now do, I can't help but feel that having kept important characters of various factions alive for the long run would have been a more fulfilling and possibly easier way of weaving his tale (he might not have written himself into that corner, for one
Drogo should have actually invaded, we should have gotten the reveal of Jon's parentage with every major player alive, pitting Robert against Ned, seeing Catelyn's reaction to the secret, Robert should have learned about "his kids", etc. The tale would still end up being about betrayals, rebel kings and civil wars while common threats loom around, with a lot of events remaining more or less the same (and we could have been spared the positioning of Joffrey and Ramsay into the forefront).
Drax the Legend, Captain of the Fist, The Starwalker, The Jade Slayer
Nah, then there would be nothing to differentiate it from any other story. While your version would be interesting, GRRM's version is more so because it's far more original.