Mr Ramses said:c) ... you play a black spell to 'destroy all creatures' ... [they] play the one that has ward [and] pick black
LOL, that's a counter so devastating I would probably laugh (or cry) if I was on the receiving end.
However it would be even more spectacular if they 'countered' the card with a fast blue, wouldn't it? (assuming that's things resolve in the destroyer's favour)
Thanks for reading and replying, all of your points are good, I'm definitely giving this deck a try when it comes out.