So what happen in 2007 when Glenn was NOT technically here but instead riding the pine all year due to injury? Yet this last season is when we lost Glenn and felt the consequences? OoooooooooK.....! We did fine without him long before he was ever gone.
The reason receivers weren't getting open deep is because our Oline fell on it's face the majority of this last season, thus our QB didn't have the time to allow those plays to develop. The problem lies squarely on Jason Garrett, not altering the playbook in the least to make up for this insufficiency we suddenly were experiencing due to our Oline's over the course of the season.
If you noticed, when Tony moved out of the pocket (Ie. started buying some time on his own) the receivers and the long plays started happening more. The problem was though, our oline was so pathetically bad at times that even Romo couldn't get out of the pocket half the time to even try before being buried up to his eyeballs in defenders trying to murder him.
Forget the WR position, we've invested enough there. Most OC's could make gold out of lead with the group of guys we've got. We need to concentrate on solidifying that Oline if we ever intend to go anywhere. Even our running game never caught hold but in a few games, and that's due to our Oline play also.
Fix the oline, a lot of other stuff gets fixed in the process.