Horizon I still haven't gotten to a novel where the game played was good. I think it's more about wish fulfillment and getting revenge on people that wrong the MC than about the game in most popular gaming novels.
I'd love to see one where the lvls had a cap, there was a real endgame instead of constant grinding, one where no op classes existed, where harems didn't form around the MC, and where skills mattered more than items. But the writer would have to have massive MMORPG experience and a decent writing talent to make it work.