Ultimate Fantasy Football Strategy has 2008 Offensive Line Rankings & Analysis and places Dallas in the second tier with a "Good" ranking. Here's the 2008 outlook:
The Cowboys offensive line will return its five starters including three Pro Bowlers for the 2008 season. The Cowboys have one of the biggest offensive lines in the NFL anchored by Flozell Adams at left tackle. This line remained very healthy last season but even if it were to have to deal with injuries, there is plenty of depth with Free, McQuistan and Procter. One slight concern is that the yards per carry average for weeks 1 to 7 was 4.8 and it dropped to 3.9 for weeks 9 to 16. This may be a sign that the line is too big and getting older. The good news for the Cowboys is there are some very good young linemen who could take a starting job away from the two weak links on the line, Kosier and Colombo. Overall the Cowboys still have one of the best lines in the NFL but the younger linemen will have to perform or age could become a problem.
More detail are provided in the full analysis.