If you include Castlevania games (which certainly have lots of stats/inventory options), those probably still have an edge (at least in 2D). I'd say that, among games that the dev/publisher markets and presents as ARPGs, Demon's Souls easily has the best melee combat.
Yeah. I was actually thinking of the first Genji game myself, as that had a system similar to DS for raising stats and getting equipment, but vastly superior melee.