Currently it costs 99 diamonds to rename the title.
First place awards 100 diamonds.
Yes there are also rewards for the skill points and some experience points...
The problem is that skill points can be bought with in game cash, not real life cash like diamonds.
Why would people spend 99 diamonds on the remote chance to win 1?
With the recent changes made to the voting system - it does make title renaming more attractive, but the cost blows it out of the water.