I have no clue what made me hate the GOW final boss, I simply don't remember. I just remember that I didn't like it at all. It wasn't hard, it simply annoyed the fuck out of me and I got tired of the battle, and just quit before I got too frustrated with it.
I finally "solved" Mogenar, to the point where it pisses me off that it got to me in such a big way as it did earlier today. When I finally beat it, I did it in just 10 minutes, if even that. He never, not once, healed himself (you can blow up the orbs he goes for in two shots - one charged blast and one normal blast).
Eh, I just hated it though, even though I finally got it after sticking with it.