Are you ever planning on implementing an autobet system? It's pretty much a must-have in 2018 as every other casino has it and you'll be left behind without it.
Also, why are you sticking with Ethereum only? There are plenty of other cryptocurrencies out there, how about branching out into something unique such as ADA or TROn gambling?
I'm not really sure if autobet system is a must feuture on a roulette game because I do not see how fun to play roulette automatically as there are many options to bet on roulette unlike dice which is only about over and under bet. I myself do not really like to play roulette, but if I have a chance to play roulette then I will play randomly by choosing numbers/row and most likely will change the numbers/row in every few bets or even in every bet. So it will be a bit hard to make autobet in roulette game IMO.