The Mosin Nagant has its place, but as a battle rifle rated against all others it is pretty low on the list. It did not influence as many other designs as the Mauser. It did not have the slick action of the Enfield. It does not have the manufacturing consistency to have the same reputation for accuracy as many other rifles from other major powers. It saw spread to other countries by either conflict with Russia or as aid to nations they wanted to influence. They were made in quantities to support a strategy of arming so many that swarm tactics would be applied. Their shear quantity has kept prices down.
I think it is a worthy rifle for what it is. But again, when compared to all the other battle rifles out there that excelled in some area or went on to influence future design, the M/N just doesn't rank that high. Shouldn't really be a huge surprise.