Did you know that 1st place in rookies is better than a 3rd place in stars!
Karma is only given if you reach the final
Think of how many rookies games you have won to the amount of times you have reached a final of stars. There have been over 100 different winners of stars and most of the time you will not get a good return on what you paid to get in.
In addition to this, Stars should give a better return on those that finish just outside of the top 3 and karma to those that finish 4th, 5th and 6th. At the moment its not really worth the gamble entering stars, you pay too much and the returns are so low :(
