The old metal Harrier could use the nozzles rather more freely. It was even part of the air test to fly straight and level at speed, pull the nozzle lever back, then note the speeds at which the lever reached the braking stop, and when the nozzles followed, their motion being delayed by air load. Jerry Pook flew the RAF VIFF trials, looking at both ACM and ground attack. He describes the results in chapter 13 of his book Flying Freestyle.
The USMC did indeed go further with the jet. I recall an exchange pilot snagging a GR3 because he couldn’t get full rudder deflection in air combat. Engineers found no fault, but on questioning, he revealed that his airspeed at the time was 400 kts! Years later, in the AV-8B, they found what happens to the big Pegasus when you apply maximum power and maximum G at the same time. Titanium friction is not good.