Hmm, depends what you're going for.
If you're going for hard, which I think you are, I think the question is how you express difficulty.
Another way of thinking of it is asking yourself this question: "What am I testing the player on?"
Currently, your game is a bit of an endurance challenge. It becomes a question of whether you can keep the rhythm of jumping once you get it.
If you wanted to change what you were challenging, one option would be to shift toward designing a bunch of different configurations the two platforms appear in. Then each pair would serve as a micro-level, a little trial to be overcome quickly before the next pair appeared.
If you went in that direction, you might want to make the actual platforming easier (as players need to take in what's going on, and then execute a plan quickly).
If you stick with the endurance thing, you probably need a way to ramp challenge up over time. Maybe a steady increase in the rhythm of the platforms appearing?
You probably need to decide what it is you want the game to be, and why you want people to play it, to answer the too easy / too hard question. Does that make any sense?