On a side note, after typing out my post on Longer, I think that Billy's stature in the club has suddenly become more apparent. I genuinely do believe that Longer wishes to stay at St Kilda, but (from what I know about Billy, based on people who know him, and also tidbits like interviews) I also believe the talk that he has issues with laziness and drive.
I would say that the club would've sat down with Billy at the tail end of this season, and discussed what it would take for Billy to regain the position as the number one ruck from Hickey after the latter's amazing season. In doing so, they would've raised their concerns about Billy's work ethic and how they do not think he is capable of dethroning Tom if he does not improve. Now, Billy, who apparently loves being at the club for whatever reason (friends? location? environment?) obviously wants to stay, so a deal was cut with the club, as follows:
The Saints re-sign Billy for 2 years. Why 2 years? Well, because they guarantee he will stay on for the 2017 season, which will give Billy the chance to improve his work ethic like the club has asked. If he improves to a satisfactory degree (maybe club intuition, or basic KPIs) then either a trigger for further years are enacted, or the club re-thinks the number one ruck position, at the very least. If Billy does not improve as they hope, then he has agreed to be traded to the most suitable club, in terms of St Kilda's desires.
I believe that this is a good compromise, as it gives Billy the extra chance, and also an extra year to prepare for possibly moving interstate, rather than being moved in this trade period. Furthermore, it helps the Saints because it'll either give him the kick in the arse that he needs, and therefore he'll become the gun ruckman that they believe he can, or it means that he will be contracted come trade time (more value) and is happy to go wherever.
Of course, this is all thrown out the window if he's traded within the next few weeks