KoA definitely has better writing and content. The main story and many of the factions, I feel, have far better questlines. While a lot of the side content was dull, there were a number of quests that were pretty worthwhile. But yes, most of the random quests were pretty dull, though I felt that most of Skyrim's main content was lackluster, so . . .
KoA's character development is a lot better as well.
Combat is pretty much depends on the player. Both games offer enough variance to offer different feeling playthroughs, maybe KoA a little more so.
The only real issue I had with KoA was that the world didn't svck me in. KoA has a decent story and a nice looking world, but I never felt I was really part of the world. With Skyrim, the actual content never amounted to too much, but the world was interesting in itself to experience. Overall, Skyrim is just more engaging, even if KoA bests it in a lot of areas.