The plan for the future is, at least on my design plans, the cultivation rate would change depending on variety of factors such as inner arts, the inner arts level, unique skills, in-born traits/talents, random events, pills/potions/herbs, artifacts, etc etc. But that's gonna be in the far future as I keep working on the game.
But in general, vanilla cultivation is always gonna be slow in this game, because you're just a normal cultivator. Unless you manage to get lucky on character rolls, fortuitous encounters, obtained other external stuff, or other things planned for the futures.
We'll see what I can come up with :)