I think most take what Jerry says with a grain of salt... Hey we know that unless there is a complete cluster ***** that Jerry won't say anything negative about anyone.
And before he was injured Costa played well in his limited appearances in 2012.
The way I look at it is... Is this offensive line better than the one in 2010? Yeah.
Is it better than the one in 2011? Yeah.
Is it better than the one in 2012? Yeah.
One might say that it was not big deal to have a better Oline than the previous 3 seasons, but I think the fact of the matter is given the competitive nature of the NFL and that you're in constant competition with each and every other team for talent, improving any unit that has 5 members in it takes some effort and better evaluation skills in order to succeed.
I don't see how anyone could look at this offensive line, compare it with the last 3 offensive lines and not deduce that something has changed somewhere.