Despite the popularity of the .30 caliber magnums, dating back to the .300 H & H in 1937 -- or even the .30 Newton before that, I think of the .30 magnums as neither "fish nor fowl". That is, ideally I would use a smaller gun on deer and a larger gun on elk. I suppose if you want to compromise on a single gun, the the .30 magnum would come as close as any.

That said, I own a .300 Winchester. If you get much larger in case capacity you are rapidly reaching the point of diminshing returns. Larger cases use a lot more powder, give more recoil, burn barrels faster, and don't really provide much in the way of useful extra velocity.

Despite the hype surrounding it, the .300 WSM can only match the .300 Win Mag in velocity at the cost of substantially increased pressures. Combined with the fact that you are subject to feeding problems with the disproportionate case, ammunition is more expensive, and the magazine is likely to hold one less round than with the conventional belted case, I find little to recommend the short magnum over the conventional one.