Pre-orders are down A LOT for AW compared to even Ghosts. We will see. With about 1.5 million pre-orders across all 4 platforms in the USA, I can expect this will probably be the best selling game this year if GTAV doesn't re-release. AW only has 225 thousand across PS4, X1, and X360 compared to last year with Ghosts having twice as much on the 360 alone.
Why would anyone pay tenfold for a game they cannot keep is beyond me. When I pay for a game I expect to be able to keep it, not rent it. Can you play Destiny ten years after the servers are down? No? Then AW is the winner in my book because it has the courtesy to offer offline MP in the form of combat training. Endless replay value = more bang for your buck.
I think COD AW pre-orders are down this year due to Destiny and partly because Ghosts left a very bad taste in the mouth of the masses. It does not matter if Ghosts is a technically sound game if the majority of the casuals thinks it's the worst and the most boring COD.
They are now voting with their wallets.
Destiny is very capable of outselling AW and probable will. Destiny caters for a wider variety of gamer, Bungie's already large player base that it built on Halo will feel very at home in the Crucible, It's co-op story and end-game content will appeal to fans of games like Borderlands.
Personally I'll be getting both as Bungie's style of MP isn't for me, I prefer what CoD offers but I will be sinking a lot of time in the story and raids of Destiny.