MH:W was my entry into the series. It seemed to have a decent amount of monsters in it for the base game. How does that stack up to earlier titles like you were saying? That being said, there definitely could have been more, but the detail into the models and the game in general may have been a factor that they didn’t include as many as you’re saying.
But now, with World behind us, Capcom might see the writing on the wall that more people are playing World than Rise on Steam at any given point on the day and sink more time into adding in more base game monsters.