Doubt he'll be in HG for long if he's indeed Parl Sec calibre. HG is opposition fortress and DC's chances in 2016 will still be slim unless something dramatic happens again to WP. So in all likelihood, DC will be moved to a sure-win GRC in 2016 (believe many had said the same in this forum).
OYK is clearly earmarked as one of the future PAP political stars. The Aljunied GRC setback may not be a bad thing for him as he has now gone through the baptism of "electoral fire" after the last GE. Hopefully, the Aljunied defeat will imbue some humility and empathy in OYK so that he is one with the people.
Not sure if he will stay in Aljunied but you can bet that you've not seen the last of him.