[Barnster]

Arguably none of the armies should be the best, they should all be balanced.

If the topics about what armies are easiest to play in 8th it would likely be Skaven H or D elves, dwarfs and chaos

So the best thats not in your list would probably be dwarves

 

[Barnster]

If you play dwarves and want to stop knghts go cannon and bolt thrower heavy. Don't rely on special characters, but rather on big units of infantry and big guns. Just take a regualar dwarf lord with 1+ save and GW with the ASF rune. Ironbreakers will hold the line, with thunderers and quarrelers.