Yes I think Szczesny is good enough. Our defence hasn't been though. - 'Squashed with experience' ? I'm not too sure I understand what you mean by that, but obviously experience is a key factor and Szczesny lacks that currently. Friedel has bags of it and I think he will be a good signing for Spurs, but I wouldn't want to see him in front of Szczesny at Arsenal.
Maybe need to rephrase it. I meant the errors might be gotten rid of with experience. I guess the Arsenal philosophy is young players, so Friedel wouldn't fit in with that. What you do need, is some experienced players so your young guys have someone to learn off. Some people to lead by example