They don't really need reinforcements in defense, they have good defenders, though most of them were not in form this season, but we can hope they improve next season, but they really need to improve their midfield, they are seriously lacking in that department, and i think it is the major cause of their failures this season. Mac Allister is a brilliant player and he is going to help this Liverpool's team so much, btw they are just getting started with their transfer business, they need at least 3 quality midfielders, one or two defenders and prolly one winger as well, i would have said they need a striker, but hopefully Nunez clicks for them next season, all of these is what would enable them to compete again.