Does the endgame content include raids of some sort?
Yes, there are 5 man raids, called Special Task Force missions (originally called raidisodes) and require a 5 player team. You will not be able to do any of these raids solo. In addition, they require a rank of Rear Admiral or Brigadier General to get the mission. Enemies found in the STFs range from level 45 to level 47. Cryptic is considering 10 man and 25 main STFs in the future, depending upon feedback from the 5 man STFs.