League-of-legends – Does Yasuo’s Last breath count as Airborne CC

It's totally random. I tend to place it in areas that are congested, like tri-bush area in jungle, the paths close to the blue on each respective side, near the wraiths, wherever there's a teamfight. Try to actively see where your jungler is, and use it when he ganks for easy assists. Also if I plan on diving my enemy I place it between him and his path to his tower.

This is anecdotal, however in response to your OP, yes it is unreliable.

EDIT: you may or may not play these champions, but if you play Karthus, Soraka, or Shen, you should have a pretty good understanding of how to watch the mini-map and be a good global presence. Use GP's Ult in similar situations that you'd use theirs. (I.E. try to secure kills or score a few easy assists, even if it doesn't turn the tide of the teamfight, you'll get cash if an enemy dies and you don't have to leave lane.)

Steel Tempest cooldown is reduced by 1% for every 1.72% bonus attack speed. Another easier way to think about it is for every 1% bonus attack speed he gets .58% cdr

The cooldown of Steel Tempest is unaffected by cooldown reduction and is instead reduced by 1% for every 1.72% of his bonus attack speed. This is capped at 66% cooldown reduction with 114% bonus attack speed. At max rank, the minimum cooldown is 1.33 seconds (1.4 attack speed). Yasuo's 4% attack speed per level is factored into Steel Tempest's cooldown reduction and cast time reduction. At level 18, Yasuo has a total of 68% bonus attack speed from leveling alone which reduces Steel Tempest's cooldown by 40%. Steel Tempest's cooldown is effectively reduced by 2.3% per level.

So to answer your question 40% attack speed would get him 40/1.72(or 40*.58) = 23.25% bonus cdr for the ability