We do have plenty of youth, you are right.
But you have to remember that regardless of age, Soliola has been playing first grade regularly since 2005, and apart from his first two seasons where he was relatively impressive, he has offered very little since. Similar to Setaimata Sa, Soliola showed little signs of improvement, and actually seemed to be going backwards.
You could say similar about Kenny-Dowall, but I see him as always the type of players who can score stunning tries and then make errors - whether Brian Smith will put up with the errors is yet to be known.
But aside from Soliola, we have plenty of youth in the team, look at how old some of these players will be next year:
Ben Jones - 20
Jake Friend - 20
Mitchell Pearce - 21
Martin Kennedy - 21
Mose Masoe - 21
Sandor Earl - 21
Tom Symonds - 21
Jared Waerea-Hargreaves - 21
Anthony Cherrington - 22
Rohan Ahern - 22
Stanley Waqa - 22
Shaun Kenny-Dowall - 22
Sonny Tuigamala - 22
Mitchell Aubusson - 23
Setaimata Sa - 23
FP Nuuausala - 23
James Aubusson - 24
Sisa Waqa - 24
Todd Carney - 24 (if he signs)
Daniel Conn - 24
Sam Perrett - 25
Nate Myles - 25
Lopini Paea - 26
Nick Kouparitsas - 26
Riley Brown - 26
That is a VERY young squad. This is how old these players will be NEXT season, so subtract a year for how old they are this year! What the Roosters need is an experienced, 30+ tackling lock-forward who can cover for Fitzgibbon's vacated workrate - someone like Nathan Smth, Matt Hilder, Michael Luck, etc. That would take pressure off our young forwards, allowing them to do what they do best, which is run hard and straight.