As you said he was bought in because of the Giroud injury, and has had 3 full seasons in this league, so while he can improve he has to be ready to perform straight away. Not sure what his potential is really. Never struck me to having the potential to be world class but I think the Adebayor comparisons have merit. Hasn't kicked a ball for us yet though so let's see.
David Dein says he 'knows' Wenger bought him to play as a striker.
http://www.goal.com/en-au/news/4019/...-already-risen" I know Arsene's bought him with the intention of playing him as a striker"
Although Wenger's definition of a striker is quite broad. He still calls Podolski, Walcott, Sanchez and Campbell strikers. But I don't think there's much chance Welbeck won't play as the CF, he's got the physical attributes that Wenger wants in that role.