Originally Posted by Cows getting bigger
the easiest solution is for the manoeuvring traffic to work around the aircraft that is trying to get somewhere
I disagree. That is only the easiest solution for the pilot trying to get from A to B. For the manoeuvring traffic, that solution probably means terminating the exercise they're currently undertaking, finding another suitable location nearby (with suitable weather and clear of other traffic), getting back into a suitable formation from which to re-start the exercise.... etc etc. If air combat training is being done 'properly' then there might only be enough fuel for 3 or 4 exercises per sortie, and re-setting effectively wastes one of those attempts. Equally, if the exercise involves a forward air controller on the ground, there is no option for the manoeuvring aircraft to 'move' their exercise; they would have to wait for the conflicting traffic to pass.
Conversely, all the transiting traffic has to do is alter its heading by 10-15 degrees with about 30 miles to go to the confliction, and all is well. Perhaps it might add a minute or so to your journey. Is that really so difficult?