Actually the Raptor is the best ground attack IADS penetrator apart from the B2. Due to its all aspect stealth (unlike that of the F35 which is neither all aspect, plus it is only geared towards X band radar), advanced kinematics (which enables supercruise, something the F35 cannot do), it has the ability to penetrate. Now, add its capabilty to carry 8 GBU39 small diameter bombs, each of which can be individually targeted, and due to the Raptor's kinematics launched many miles away, and one Raptor is far more lethal than several F35s when it comes to advances IADS penetration.
According to the Air Force website the F-22 can carry 2 1000 lbs JDAMS in the ground attack mode. The F-15E can carry many more and at a fraction of the cost of an F-22. Boeing has upgraded the design to make it stealthier than older models, though not as stealthy as the F-22 it could certainly improve survivability. A mix of F-22s for air superiority and new, upgraded existing designs would be a more cost-effective solution to the F-35.