Most of my friends who state the game is too hard normaly have a melee-heavy party and normaly jump into the fights with all charging-in to the enemy.
In most games that can work, but on this one it actualy hinders your party a lot, because most of the beauty of the game is elemental combinations that form powerful AOE damage and explosions and stun states on enemies, but have also friendly fire, so melee a lot of times just gets in the way of those AOE setups.
Just play a little bit more defensively and put your melee guys with some ranged capabilities and the game plays out much more like a chess game and less like a slaughter house of melee action
Send in some pets, do your magic AOE chaos on clumped enemies, fly some ranged attacks on them, and let your melee take over the enemies that are out of your AOE fire/poison/electicity.
