Does not look much like a hammer either...
As to the last... Actual war hammers, that is actual hammer-like objects used as weapons of war, often did not look like what
we would call a hammer.
The important parts were a blunt surface to deliver the impact of a considerable amount of mass over a comparatively small surface, thus concentrating that impact, and usually a handle of some length, to add leverage. The theory was similar to that of a mace, except where a mace is of a uniform size "all about", a war hammer was a striking surface on one side, and a spike (or sometimes blade) on the other.
Mjolnir, in fact, although very good looking in a comic-book sort of way, didn't resemble most war hammers at all. Not only was its head of a shape that did not reflect actual weaponry-- historic
or mythical-- but the handle was too short, more suited to a mace than a hammer. (That, at least they got right from the myths!) As to the design, well, Lee and Kirby knew comics, yes, but didn't know squat about myth except that Thor was "this guy with a hammer". So they designed the look of Comic!Mjolnir after the only hammers either were familiar with that weren't used to slam down nails-- the Sledgehammers of the various teams working on the streets of New York.
So, really, as far as weapons go, Stormbringer looks more like a hammer, than, well... a hammer.