Master Yi's "Alpha Strike"

Why can Master Yi completely disappear from the game for an entire second with such a low CD? The damage that "Alpha Strike" puts out is fair, the distance travelled is fair, the amount of time it takes to initiate seems fair. The only question I have is why on earth does he absolutely disappear? Projectiles previously fired miss if they collide while "Alpha Strike" is engaged. This includes (but is not limited to) turret fire, Caitlyn's "Ace in the Hole", Lissandra's "Ring of Frost", and (here's a big one) Karthus' "Requiem". Some of these abilities are GAME CHANGING ULTS, and NONE OF THEM ARE SKILLSHOTS. Like I said, the ability to dash in any one direction isn't a problem; the fact that Yi completely disappears from the map (his player icon even vanishes from the minimap) is unbelievable, he can legitimately prolong his own life by using "Alpha Strike", and he already has "Meditate" and for an assassin, that's more than enough.

Now, I understand that there are other abilities that produce similar results. For example, Braum's "Unbreakable" will block anything that come's in contact with it, and mitigate's all damage from the first projectile. However, Braum is a tanky character not meant for major damage but instead for support and CC. Along with that, "Unbreakable" is Braum's only self-defensive ability. Master Yi is an assassin who already has "Meditate" which is an amazing defensive ability for an assassin (in my opinion). With this in mind, "Alpha Strike" can be used defensively, VERY effectively with practice. Abilities such as Akali's "Shadow Dance" and Katarina's "Shunpo" and even the summoner spell "Flash" bear resemblances to "Alpha Strike" but with one major difference: "Shadow Dance", "Shunpo" and "Flash" are instant teleports and do not cancel out non-skillshot abilities (i.e. Caitlyn's "Ace in the Hole"), and note that the champion does not disappear from the map entirely, but merely instantly closes a gap.

Now I also understand that while "Alpha Strike" is engaged, Yi becomes untargetable. Forgive me if I am ignorant of the description, but if Yi has already been targeted by a non-skillshot ability (lets use turret fire in this example) before he uses "Alpha Strike", should he not still be hit by it? The way it works as of this moment, "Alpha Strike" (when used properly) rivals "Zhonya's Hourglass" and/or Kayle's "Intervention". That's a bold statement, but in a way, is it not accurate in the slightest?

With all of that said, I am not an angry nerd-raging loser who got ganked by Master Yi only twice in a row in one game and decided to vent in forums. I actually enjoy playing Yi (especially in the jungle), and he's almost unavoidable in blind ques. I've made efforts to play character's who specifically counter him, such as Lissandra and Trundle, who do very well. I simply feel that he needs to be tweaked a bit to balance correctly with the game. Also, if (by chance) this isn't necessarily supposed to happen when Yi uses "Alpha Strike", then I urge Riot to take a look and observe numerous uses of the ability, because I have witnessed many of these occurrences first-hand.

Thank you all for your time. I look forward to your feedback!