My friend that plays Skaven tailored his army (still using 5 warscroll w/ 2 heroes or 1 hero & 1 monster) to face my steam tank/war altar and it was much more even. He brought a warp fire cannon and 5 warplock Jezzails. Technically this match up still should have favored the steam tank since he couldn't match my range. After a couple of rounds staring at each other and missing with my steam tank, I decided to get the war altar in range. That was a mistake. Both of those Skaven units can deal mortal wounds and the Jezzails have a -2 rend on the wounds that aren't mortal.
My DGK never got to roll a hit. We only made I through 4 rounds before we had to end it early and at that point all I had left was some of my Greatswords, steam tank and the Warrior Priest. I had taken out his storm vermin and warp fire cannon but he still had all of his Jezzails, grey seer and a hell pit abomination (that I had been avoiding all fight). It would have been interesting to see the outcome but it shouldn't have been that bad for me in the first place.
Made me think that high elf Phoenix Guard would be handy but really my troubles were self induced by blinking first in the stand off even though I had the only unit able to make attacks.