There's no way I'd drive a 25-06 over a 243Win today,due simply to the disparity in their respective boolits. The 6mm's are far more slickery,will slip conditions better and do so in a shorter action,burning less powder and with lower ES/SD(vertical),while happily housed in a 2.8" box.
You forgot to mention a fast twist barrel is required to stabilize the high BC bullets needed to achieve such an advantage. Very few factory guns have the ability to stabilize a dtac, vld,amax, etc. Not saying some can't, but majority...likely not. Apples to apples, I say advantage 25-06.
