If the guy is most comfortable playing out wide, I hope Wenger plays him there. His obsession with trying to fit square pegs into round holes has cost us over the last few years, leading to players feeling annoyed at constantly being played out of position and fragmented performances due to the players feeling uncomfortable in an alien position where they've never played before.
I think Walcott, despite his faults, is a very effective player for us, so I wouldn't want him to consider his position. However, if Gervinho does take Arshavin's position, I doubt he could do any worse tbh, especially given how shockingly inept most of Arshavin's performances last season were. However, I would still have preferred Wenger to have a signed a more experienced player instead of Gervinho, because I still don't think Wenger's learnt his lesson in terms of signing top quality players, who have cost a bit in the short run, but will more than make up for that with consistently excellent performances over a long period.