I agree. "Long Range" and ".458 Win Mag" don't belong in the same sentence.
If a long range "hammer" is the goal, .416 Rigby and .404 Jeffery is where I would start my search.
That being said... .458 Win Mag is a fine cartridge. It's very tame for a big bore, even with 'nasty' loads. It's such a pleasure to shoot, that I've hunted squirrels with a .458 WM Ruger M77.