There just running out of ideas
Not really, considering the upcoming update is going to have tripwires, pyramids, enderchests, jungle ruins, villager trading, villages that adapt to their biomes, TNT traps in the world, emeralds, an adventure mode, improved creative GUI, and boats that are easier to control. Additionally they've added some smaller tweaks like a better gravel texture and improved options menu. If anything, they're just getting started on new features seeing as how the Bukkit team is now a part of Minecraft dev. Although I too really would like an update. Can't wait to make a new world and try out all the new features.