Frost is good as long as high-level monsters have immunity to frost.
Potions are good as they are. I remember that in Diablo it's the same thing.
Nay in diablo II when you drink a potion it doesn't instantly fill up your health it takes aprx. 3-4 seconds to do it and it does so by like regeneration lets say if a healing potion heals 40 hp in 4 seconds it heals 10hp per sec like that it is more realistic you don't just swallow down the whole potion