My friend got this, and we spent six or something hours through the night to beat it. I was pure Magic Blue Knight. pomegranate sucked hard. At the end of the night, I was level 17, and the other two guys were 23 and 21 because I couldn't hit enough times to gain exp. Against bosses, I did fair damage and got alright exp because I could multihit with my RT+Y but against normal monsters, I'd only be able to hit once with it to freeze despite seven bolts coming down so I got pomegranate exp. And I died really easily so I couldn't run in and juggle everything.
Anyways. One of them went Pure Attack, and then started working on Defense, and the other maxed Attack and Magic. Neither of them ended up dying nearly as much as me because they could kill everything so fast with their physical or magic, so I usually ended up dying the most. Neither of them really needed the extra Defense though it helped a bit in the end. I don't know why your friends died so often.
Anyways. One of them went Pure Attack, and then started working on Defense, and the other maxed Attack and Magic. Neither of them ended up dying nearly as much as me because they could kill everything so fast with their physical or magic, so I usually ended up dying the most. Neither of them really needed the extra Defense though it helped a bit in the end. I don't know why your friends died so often.