f13.net

I am playing a Demon Hunter and am having huge amounts of problems with Diablo.  I can get him to the shadow part and I am now getting him to about 10% life.  This fight is really lasting imho too long, and I don't seem to be doing any more than a sliver of damage.  It takes me about 15 minutes to get to stage two.  I can't really get him beyond 60% in stage two.  Any advice/tips?

Right now my primary attack is the Bola + thunder rune, secondary is Elemental Arrow + Cold Rune.
I am using the Vanish + Extension rune, Marked For Death ability out of summoning.

What am I missing/not doing?

Edit:

So I made it to stage three, wow how cool is this that he reverts to Diablo 2 abilities, surprised the crap out of me to see the hellfire stream go through the rock.  Great times!  God I loved that and this game!

My solution to every problem in this game is to buy the highest-DPS weapon possible from the auction house.

and for DH the "easy" way is to just use the smoke screen and during it highest dps skill you can get (my favorite atm is rapidfire with rockets). Add to that the bat pet (for higher hatred regen) and it's just kiting until you can pop the screen and offload all the fury (you can in 3 seconds). Rinse and repeat.

Yeah, Diablo seems like he's just a kiting fight for ranged classes.  No other way to go about it but run and wait for opportunities to do damage. (Or use turret skills and cheese him around the pits on the two maps.)

On normal and nightmare you can barbarian cheese it with bash and the clobber(35% stun run) basically you keep diablo chain stunned nearly the entire fight, getting maybe a handfull of abilities off.

Unfortunately...stun stops working on bosses in hell.