Maybe, maybe not.Agree with most of what you say but if Sezer stays fit and healthy there will be enough demand out there from clubs that would want to sign him for a season or two as a starting half, so I'm not sure if that was the case that he would stay here as a second string half.
He could definitely end up having some options.
I mean we plucked him from Super league.
True, when you need a halfback you need a halfback (unless your the WT and will persist for Decades with a 5/8). I reckon though most teams needing a halfback would go Fainu/Galvin and then settle for Sullivan. As Sezer probably has about 2 years of playing ability in him at NRL level.
Reserve halfback would suit him perfectly. Less injuries, less gametime. Can come in during Origin and play for a few weeks then go away.