Let me start by saying I was always a Newman fan. I think he was very under appreciated while he was here, mainly over his last few years. That said, while he did miss a few games, that was not really his problem. He was tough and played hurt quite often, but that was the actual problem. He seemed to be dinged up or hurt every week. When you combine that with his age and salary, I'm sure the Cowboys (I know I did) started looking at the odds of those dings getting worse and taking longer to heal as he got older.
Sometimes you guess right and sometimes you guess wrong, but once a player hits 30, if you think the odds are against him giving you 16+ solid games, you are better off letting him and his higher cap hit leave. It's sad when that means letting someone go like Ware who has been a great player, teammate and person for the team for so long, but in the end, the system leaves you few choices. You cannot expect a player, who probably has one last great contract in their career, to take a fraction of their salary nor should you blame the team for not being willing or able to risk the cap hit for keeping them.