Honestly i could see it working out for the Raiders in the short term but the cost is way to high and will hurt them in the future. Neat chart on average age of each team:
2011 NFL age ranks: Calling all graybeards - NFC West Blog - ESPN
Raiders are 15th, but likely will be a little older with the addition of 31/32 year old QB and the lack of young "keepers" from the first round in 2012 and 2013. The Redskins are the 5th oldest team for comparison. Cinncinati is the 22 oldest (so theyre pretty young)