Walcott hasn't been messed around in terms of position. He's not good enough to play as a lone striker, lets be fair - at least not in a team that wants to challenge for major honours. Media seem to go on like he's Ian Wright or Lineker, which is how good you need to be to succeed as that kind of forward.
Wenger had the right idea trying to develop his game. All the young players he signs start out wide, or deeper in midfield before he gives them the the crucial #10 or #9 positions in his team. In Arsenal's current position mind with their striking options it probably is the best option to play him there, but that's more an indicament of the position they are now as a club and a squad.
Would take him in a shot, like. Just not good enough to be upfront in a SUPERCLUB.
Where would you play him though? Hatem is better ( goes without saying) and i think he would be pretty ineffective down the left unless you're thinking of 4-4-2 and playing him with Cisse of course.
Hatem and Walcott are completely different players with different strengths. In terms of effectiveness it's very naive/biased to suggest Hatem's clearly better. He's not.
I was going to slate this but I sort of agree. In terms of footballing ability, Hatem is miles ahead. Effectiveness? Walcott will always have blistering pace which can destroy teams, even on an off day. Would happily have them both, though