I have the Prime 1 AO Deathstroke and I absolutely love it. I have every intention of picking up a 1/3 scale Batman (if Prime ever gets around to a Arkham Asylum/City Bats) and displaying the AO Deathstroke with him (I even have an empty spot right next to my AO DS just waiting for Bats). However, keep in mind you're talking with a HUGE DS fan. I have zero issues having 2 large DS statues in my collection. Hell, Tweeterhead even announced they are going to release a 1/6 classic Perez Deathstroke in their DC Super Powers lineup. Don't think for a minute that I won't be all over that as well given my love for the classic Perez costume.
OK, back to your thoughts now. I personally think the New 52 Deathstroke and the AO DS are fairly similar. They both have a very practical and tactical look to them. In that case, I can see a collector wanting to sell the AO DS to pick up the New 52 DS. It makes perfect sense, especially if you don't plan on buying any other 1/3 statues for your collection and your collection consists of mainly 1/4 pieces. That would make the AO DS an oddball piece in any collection. So yeah, I can definitely see you selling the AO DS and replacing it with a 1/4 scale New 52 DS. Think about it. You can have one 1/4 DS you like in your collection and more importantly, you won't have to settle for the inferior Deathstroker PF. You can have 1 (hopefully cool looking) DS statue in your collection and call it a day. This isn't an option for me because I absolutely love the AO DS and can't sell him. However, this option could easily work for you.