Well these are my somewhat long-winded ramblings, for what they are worth (based on spending the last 15 years or so watching an awful lot of professional dance courtesy of a dc's career in it, a friend who is in the Royal Ballet Company, a contemporary choreographer relative and several other friends currently in major musicals) 
Craig was absolutely right in what he said about Ashley and breathing in her contemporary dance. She's a professional dancer, and he was judging her on that basis, and the contemporary technique of breath control in contract and release was what he was referring to.
Craig was also right in voting to save DDJ because he could see that DDJ had taken his earlier corrections regarding too much energy in that dance and to relax, and in the dance off he did what Craig had told him to do. It showed, and he knew it showed, you could tell by the way he was smiling. Craig knew that he had done it, and that's why he had to vote for him.
Shirley - yes, blatant favouritism is rife in the dance world, and in competitions. But on live tv? Rein it in a bit, love.
Dave - I thought you'd be a better judge than you are.
Bruno - love you to bits, and you are a damn good judge. But your largely accurate analysis is getting lost in all the hyperactive armwaving and excitement.
Wardrobe - OMG, get a grip.
Sets and props - ditto.
Production - ditch the pissup-in-a-vodka-bar Clauditorium, ditch the sob stories, and like other pp's say, get the music right. Stuff that suits the dance style. Apart from anything, it is a darn sight easier to dance to.
Stagehand on the smoke machine - turn it off.
Showdances - agree with what a lot of others have been saying. Get back to what the pro dancers are good at (proper spectacular latin and ballroom showdances), and leave the showdance stuff to the professionals in those genres. Because at the moment they are painful for me to watch, and they show up great gaps in technique.
Tap dance - nobody on the show would be any good except possibly one, but it's too late because he's gone now
Contemporary - nobody but a professional would have a hope in hell of doing it properly, the judges don't know enough about it, and nor do the professional dancers.
Choreography - credit where it's due please.
DDJ - no wonder people kept saying he looked stiff. So would you be, he's pushing 60 and trying to retrain ingrained muscle memory. Try imagining what his dancing was like 30 years ago. He and Bruno had a very similar career path... And I reckon you know which one was the better dancer... don't you Bruno?
Dance-off tiebreak - head judge shouldn't have the casting vote. If it gets to 2-2 then they should have a tiebreak. Count up all the votes cast by the judges over the whole competition and lowest goes. Tied again? Add in the audience votes.
Judges panel needs a re-think, and I'd like to see someone like Anton or Brendan in there.
And finally - its a dance competition. Mark the dancing properly.