I remember Norg being hard when I first played the game and didn't know how to junction, but then again, so was Diablos, and I offed him in my first try.

Fujin and raijin might be moderately difficult, too.

And I've passed the missle base and BGH251F2 wasn't all that hard. He only beat me once and that's because I made a stupid mistake. I'm in Balamb Garden now, and I carded for fun I attempted to beat a T-Rexaur. I had to use card, though, so I didn't gain exp, and it wasn't difficult in the least bit. I'll be fighting the Oilboils within the hour, probably, unless I quit and do something else.