Obviously the F-15E is a better multi-role platform than the F-111 but for deep strike, the USAF lost range and payload when they retired the 111s in the 1990s.Just to give some perspective of how much range the F111 had, its internal fuel capacity was ~33,000lbs. The F15E with CFT is ~23,000lbs and the Tornado is ~11,000lbs.
Drop tanks aren't a panacea, nor is inflight tanking. Drop tank and associated pylon drag means only about half of the fuel in a drop tank is used to propel the plane forward, the rest is used to overcome the tank drag. IFR SOP is for a plane to hit the tanker with no more than 45% of fuel used in secure airspace, so that if tanking fails the plane can divert to home base like occured on many Black Buck missions. However if for some reason (fighters, SAMs, no airspace permission) the tanker can't loiter in this 45% sweet spot then the usefulness of IFR reduces.