This is quite difficult to answer. Gamblers have "different" taste.
But having multiple games would always have an advantage over a single game because the casino offers multiple games does not affect that single game anyways so having multiple games is best for any casino but only as long as you can manage the users and don't get crashed. Recently goosebet opened and they offer a few games but the website was lagging so much I had to just stop betting there once my deposit was lost.
Building a reputation doesn't purely base on the numbers of games.
That is very correct and once you have a good reputation it is easy to run the casino with just a single game and unique features and giveaways. I feel more than games and anything people love to see getting bonuses from time to time and that is what a few casinos know and hence some casinos are so massive while others can't even manage operational costs.