The older race had more winners, did you participate when they had bigger prizepool and more winning spots?
Cryptodice has just changed to the new race with lower prizepool and lower number of winning spots.
It is reasonable why there are 5 winning spot only, if cryptodice want to have more winning spots then they should add more funds on the prizepool.
As it will not make senses if cryptodice have low prizepool but  have many winning spots which will make winners get so low prize.
I think cryptodice is still doing something I call experiment, to see which kind of races is the best for them as well as for players so there is still a chance to see a change on the race in the near future.