It's a strange question, that can only be answered by the individual.
Honestly, I don't think Saints supporters would have cared so much if he did leave, but achieved 2 premierships.
When Ross left, one of the main criticism was he left the list in a "terrible state".
If say for example, Ross did get the Saints 2 premierships, in my opinion, the whole "leaving the list in a terrible state" wouldn't have been an issue. After all, he achieved ultimate success, but as a consequence of that success, the list would have to be re-generated at some point in the future.
Is your list really that terrible? A year later and your squad needs a bit of regeneration but name a team that hasn't come to the end of sustained finals footy that hasn't been in that situation.