The Ring's corruption forms

[Raynor]

Originally Posted by Legate

the idea of "Gollum the Great", I believe, took shape only as a response to the humiliation and wrong treatment he suffered from everyone since he once again came to the "outside world"

In my opinion, this came much earlier:

Originally Posted by Letter #246

It was part of the essential deceit of the Ring to fill minds with imaginations of supreme power.

Also, as quoted already in this thread, even Sam fell to this, although he had the ring for a far lesser period of time than Gollum did. Insofar as what Gollum's induced temptation would actually imply for him, I believe it is evident from the context that it is by and large not related to ruling others, but limited to procuring/eating fresh fish three times a day.