As I said on the other thread, I think that as fans we now have no alternative but to accept the new normal in terms of our club's position. Make no mistake, both the appointment of Arteta but more importantly the direction that the club has now taken in building with young players (not to mention the significant investment) is no short term fix, and the sooner we accept this, the happier I think we will be. Whether Arteta has what it takes to make this work is yet to be seen (and its completely understandable why many Gooners are sceptical), but I agree that we need to be careful who we wish for as an alternative - particularly at this stage. Again, I think we need to get our heads around the fact that it is unlikely that a so called 'super manager' would wish to come in and develop the squad (we aren't going to reverse our decided policy and try to buy more immdiate success at this stage, nor should we do so - and we are firmly out of the upper echelons of Europe for a while - so I just cant see the incentive for an established manager with a track record of success to come to Arsenal).
As you say, other than this we are left with relatively inexperienced managers or has beens, and we really do need to be careful what we wish for here. The latter could screw us up even more, and the former would be replacing Arteta like for like.
So yes, I think we need to sit tight and hopefully enjoy seeing some progress now, rather than expecting even top 6 this season. Perhaps there will be less angst if we do.