To be fair, apart from Andrew Johns...can you name a halfback that has put a team on his back and taken them to the title?
By "on his back" it needs to be an example of a halfback with no recognised 5/8 next to him and lacking depth generally (which has been DCE's situation for the majority of his career - remembering he did win with Foran). Thurston couldn't - he needed Morgan, had Taumaolo, Jake Granville in peak form and Matt Scott etc.
Cronk had the two best teams in decades at his disposal with the best hooker in history at Melbourne along with Finch, Widdop, Munster etc. Then he had Keary and the sombrero gang at the Roosters.
The Sharks had a tough, talented and well balanced team with a solid half-back who certainly didn't put anyone on his back.
I can't think of anyone other than Andrew Johns who won with Sean Rudder next to him, and even then he had Buderus and a star backline.
As for an extension, I totally agree that we should not sign him on the kind of money he is on now - no more than 900K given his age etc. I would also be happy to move onto a younger promising player; however, I think the narrative of halfbacks carrying their teams is a little exaggerated at times.