The only real difference between the 8x57 and 7x57 case is that the shoulder on the 8x57 is further forward by 0.099". It does then have additional case capacity. Enough to be worth the effort? Hard to say.
I like the 7x57 as is. If the 7x57 is built on a standard length action, leade allowing, you can seat bullets out to a longer COAL and thereby increase the case capacity without resorting to any wildcat shenanigans.
But if it scratches an itch you have, have at it!
If I have the need for more capacity, I bust out the .280 AI.
