On Standard and smaller maps, if you fail to secure a religion you are creating an opportunity for the AI to easily obtain a religious victory. I realize you can create holy sites in different cities that have different religions and create missionaries to avoid a predominant religion but there's still chance involved that you've obtained the religion you need to fight of predominant status.
OTOH given a healthy faith giving pantheon religious victories are the easiest to obtain. I would recommend increasing the amount of cities required 67%-75% OR making it such that converting cities after asking them not to convert results in a Casus Belli. I'm sure I could have done better to avoid defeats but this is the only thing that trips me up late game. Barring these changes I'm going to focus in on obtaining a religion every game.
OTOH given a healthy faith giving pantheon religious victories are the easiest to obtain. I would recommend increasing the amount of cities required 67%-75% OR making it such that converting cities after asking them not to convert results in a Casus Belli. I'm sure I could have done better to avoid defeats but this is the only thing that trips me up late game. Barring these changes I'm going to focus in on obtaining a religion every game.