I thought Goro was bad but Moloch is horrible.

"Moloch must die...." - CHiPs (the 70's TV show)

Perfect example of a Moloch Vs Kano battle on hard setting:

1) Match begins.
2) Kano either takes a step forward, takes a step back, or attempts a punch\kick.
3) Moloch uses his 3\4 screen reach to whap you with his ball. Twice.
4) If you are more than half a screen length away (after zooming back), he sucks you in with his silly breath thing.
5) Kano gets up, attempts to punch.
6) Moloch counters by grabbing your head and slamming you against the ground.
7) If Kano's remaining life > 0, goto 2.
8) Throw your controller against the wall while Moloch has "450369 wins" showing in his life bar.

I just can't play arcade on anything higher than medium, and even then, I've had to use Jax to get through Moloch.

I'm using scorpion and I get just about the same results. I figured out to switch to the sword and get in close, using the special button I can dodge most of his hits but as soon as he gets one shot in I am done.

I've had to use Mavado on Moloch. In fact he's the only guy I can beat him with.

I haven't actually played enough to get to Mavado yet, but this certainly reminds me of my MK2 games. I'd always play as Kitana or Shang Tsung against Shao Khan. Those were the only two I was able to beat him with. I'd make sure to play against Jade so I could then switch to one of my two winners (even if I did cheese the win)