User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-26074976-20140126162927/@comment-1475794-20140127142544

TNB12, I'd like to add some facts here related to weapons.

The 1st Japanese MH game for the PS2 didn't have Dual Swords as a weapon of choice but it was added to the 1st expansion on the same console which was named MHG.

MH2 for PS2 introduced 4 new weapons, those were the Long Sword, Gun Lance, Hunting Horn and Bow.

MH3 omitted the Dual Sword, Gun Lance, Hunting Horn and Bow but added 2 others which were the Slash Axe and Middle Bowgun.

MHP3rd returned all the previous weapons without the Middle Bowgun with new move sets but no underwater combat.

MH3G returned underwater combat which means new moves for all weapons.

MH4 added the Charge Axe and Insect Rod with new moves for all weapons due to Aerial Combat.

So there is a slim chance that we may have a new weapon or new move sets or element and ailments for weapons but I highly doubt that underwater combat will return.