So hard to give an accurate answer, I wil have first stab:
1 - Brett Finch (Sydney)
2 - Paul Rauhihi (NQ)
3 - Jason Cayless (Sydney)
4 - David Kidwell (Melbourne)
5 - Matt Cooper (St George)
Brett Finch has grown as a player under the coaching of Ricky Stuart though I will not harp on why I think he is going to turn out as a top half in this competition. Last season he was second to Danny Buderus in the Dally M vote and was the Roosters best in 2004 taking over alot of the kicking and playmaking duties.
Paul Rauhihi has gone from strength to strength in NQ and IMO this would have alot to do with Graham Murray who is one of the most underrated coaches in the NRL. Rauhihi was the Dally M prop of the year in 2004 and with O'Meley and Price, the most dominant prop in the NRL. To think Newcastle and Canterbury let him go...this season he made those decisions look rather lame.
Jason Cayless has all but removed himself from the shadow of brother Nathan the Eels captain. He was brilliant in the tri-series and was instrumental in the go-forward for Sydney. I remember him at Parramatta as a average to good player who took a back seat to Vella, Cayless and Hindmarsh...he is now a forward with a healthy amount of respect in the NRL.
If we are talking about improvers in the NRL, Kidwell is right up there and possibly higher for mine. He was awesome at times this season and played like he has a 'chip on his shoulder'. Probably the best season I have seen from Kidwell.
Matt Cooper is the best defensive centre in the NRL and has held his own in a brilliant at times backline for St George. 2004 saw him earn rep jersey's and most say he was unlucky not to start in alot more tests in the tri-series as IMO he is alot better than Berrigan as a centre.
There are my nominations for now. No doubt there will be posts where I go "crap, I forgot about him". You get that though.
Notable Mention(s):
Jamaal Lolesi IMO rates a mention as he was a so so player in Canberra who could sniff out a try. This season at Canterbury he more than held his own and played a key role in keeping Utai in premiere league. He is a good finisher and solid defender, he has improved over the last 2 seasons and Folkes recognised that when signing him at the end of 2003.
That will do me for now it's 1.32am. ;-)