Why does Lee Sin have 7 abilities?

Q: Projectile then dash if projectile hits something. Understandable and kind if necessary to function. Damage is release Bayonetta ladder combos level of stupid, but whatever, not the point. W: First cast grants a shield to him and an ally, second gives life steal and spell vamp. Why does he get a second cast that gives him nothing but extra sustain, on top of the shield? E: High damage burst, followed by a second cast for a strong slow to all affected targets. I don't want to suggest giving the first cast of E more power by including a slow on the base, but why even bother with the second cast since you'll just likely double tap E immediately?

The only reason I can think would be that he was designed to auto attack a lot more often, weaving his autos using his passive between his abilities. Since he's one of the champs who is balanced around "how difficult he is to play," (Other examples being Riven, Kalista, and Azir before the latter two being dumpstered due to being pick-ban in every LCS and upper elo game) and his combo against champions doesn't utilize his passive and autos that much, wouldn't it make more sense to just apply the bonus affects to the normal casts (except for Q)? Would probably make him easier, albeit only slightly, thus more prone to balance changes, aka nerfs that he needs, which I don't want to discuss right now because that's a thread that has been created numerous times.

Who am I kidding though? The LCS Jungle posterboy will always be kept overloaded.