For me simple and selective or unigue games is good because having lot of games will make the site looks not familiar eve after many uses.
Having instant deposit and withdrawal for crypto currencies will make them as good one.
I have an opposite opinion about this. If a site has a lot of games, it means they will attract all kind of people and people will not have to move to another sites in order to find their favorite games.
Secondly all the good sites have instant deposit and withdrawals and hence this feature is not something unique.
So we can conclude that the site should have a lot of games, the gambling site doesn't have KYC, instant deposit and withdrawals is needed in the gambling website, have a bonus welcome and rain bonus too for the gambler in the chatbox, have a faucet which will attract more player to comes. I think if the gambling website can have all of these, they can have many gamblers that will stay on their site.