I played it on Hard mode.
Well for the first phase of the fight it is mostly easy. Except for the part when you reduce his hp to around 15% hp? He would keep flying away. When he lands, within less than a second he would fly away. That would be the only hard part for me. Well mostly because of spawning the stick of doom, (the impaling thingy) since it takes away a chunk of health.
The second phase of the fight was a real pain since there is a constant loss of hp. It is a pretty long fight considering you have to reduce his mana to zero. Though... I really miss that Magic Hammer mana burn. To make things worse, Yurgimar disappears and leaves those three circles where you have to get your characters to stand on else you take a crap ton of damage. I lost around 12 lives just in that second phase of fighting Yurgimar.
Perhaps like TrueZozi said, nerf the second phase a little. That hp drain rate is pretty fast considering its a very lengthy fight. Overall it is a challenging boss battle and rather enjoyable in my opinion.