Campaign replayability by choosing the difficulty level?

I would like to suggest that every campaign now available (inc. challenges and BW's Warroom) could have an option to choose the difficulty level. That way there is more replay-ability for the campaigns.

For new players it would be nice to even try to crack the BW stuff with lower difficulty level first and then try to pass the same maps with increasing difficulty levels. (easy-medium-hard-expert etc)

Same goes for the easier campaigns; It would be great to try to pass them with higher difficulty once you have cracked them with easy/medium.

Also some kind of indicator to show which campaign level you have passed and with what difficulty would be great. That way you could follow your progress.

Naturally it would be even better to have new campaigns (I don't play online, ever) but I would imagine that tweaking the current campaigns could be less work (though how would I know, i don't code).