If we assume that Santi is coming, Wilshere wont be back for the first half of the season, and RVP staying(highly improbable)
--------------Szcesny---------
--Sagna-----Koscielny---Vermaelen---Santos
-------------Arteta------Song--
--Theo---------Santi----------Podolski
---------------RVP
To be honest, i think playing Santi there might not be the best idea, but I'd prefer having him there than having to alternate between the extremely inconsistent Rosicky and Aaron Ramsey. I'm hoping there is truth to the Sahin rumors, and that it goes through. In that case, i'd play Sahin in a more withdrawn role as a CM alongside Arteta, with Song screening the defense. I'd drop Theo, and play Santi on the right with Podolski on the left. I even wouldn't think that it would be such a disaster if RVP left, in that case.
Though with RVP and those two signings, I really think our midfield and attack will be almost as good as any team out there in the EPL.