I'm not a Clarke fan but I'd like to see him given a chance to improve. There have been some other guys who were pigeonholed as ODI/Test batsmen only who have managed to find success in T20. The world cup might be the wake up call he needed.
Haddin is a strange case for me, as from what I've seen hes a naturally attacking batsman. I would of thought T20 would suit him just fine.