In my opinion there is nothing wrong with the Win Mags, Weatherby Mags or newer RUMs. But no, they are not generally necessary. In fact, the real reason for them, IMHO, is to extend your hunting range - or more correctly, your hunting area.
As I have said on other posts or forums, its kind of like comparing a 9" and 12" pizza. The radius ("range") of the larger pizza is only 6" compared to 4.5" for the smaller one -- an increase of only 33%. But the total AREA of the larger pizza is a whopping 77.8% greater.
There is, however, the law of diminishing returns. At some point you have a cartridge that shoots flat enough that most hunters will never shoot game beyond its capabilities. The reason may be that they don't feel competent at further ranges, or maybe that they have no problem simply closing the range. But there are others who practice the long shots and are competent to take them. If they are hunting an environment where longer ranges are to be expected, I see no reason why the Magnums are not appropriate.
One should always remember, too, that the Magnums can be downloaded if desired, but the standard cartridges can never safely reach Magnum performance.
So what do I shoot? A couple of Marlin lever guns (.375Win and .45-70), a couple of muzzleloaders (both .50 caliber), a .44 Mag carbine, a .257 Roberts and a 7mm Mag. Longest shot I have ever taken was 350 yards for a 6x5 bull elk, one shot, and about 290 yards for a buck antelope - everything else was 215 yards or under.
So, no, I don't have any super-whiz-bang-ultra-mags, and no, I've never needed one -- a .30-06 would have done everything I ever needed. But that doesn't mean I won't get one. Kind of have my eye on the .338 and .375 RUM. Why? Because. And thats all it takes to make them "sensible" cartridges, IMHO.
Oh, yeah - one other thing...
Recoil on the super-whiz-bang-ultra-mags? Take an unscoped Marlin 1895 with the standard hard rubber "pad" and drive a 460g hardcast to around 1812fps. :shock: Then come talk to me about "recoil". :wink: