Lee Sin's ult is pretty overloaded to be honest
Lee Sin's ultimate does a ton of damage, has an absurd scaling, and is a strong displacement (knockback).
On top of that, it has a very low cooldown for what it does (and it has A LOT OF uses). At least when compared to other popular junglers' ults.
Ivern: 160/140/120 cooldown. Summons a controlable pet that can knock up enemies ONLY when they have 2 stacks of its passive. Vi: 150/115/80 cooldown. Does damage (150/300/450 +140% bonus AD). Knocks up a single enemy (knocks aside enemies in her way). It cannot be flashed from but it can be countered by things like Zhonya, Tahm's W, Morgana's blackshield. Rengar: 130/100/70 cooldown. Makes him camouflaged. Does a guaranteed critical strike but it has no CC (Rengar has CC on his empowered E, but it is single targeted and it is a skillshot) Kha'Zix: 100/90/80 cooldown. Does no direct damage. Makes him invisible. Does not has any CC even when evolved. Hecarim: 140/120/100 cooldown. Does damage (but it scales with AP, Hecarim never builds AP or magic pen). Makes enemies in an area flee. The thing is, flee can be countered by tenacity and QSS. Zac: 130/115/100 cooldown. Does magic damage (Zac usually builds no AP and magic penetration) and knockback enemies in a short area. Graves: 100/90/80 cooldown. Just does damage, although it is 250/400/550 +150% bonus AD
Lee Sin: 90/75/60 cooldown. 200/400/600 (+200% bonus AD). Instantly root an enemy for 0.25 secons (meaning you can't escape from his ult). Knocks back the targeted enemy, in addition to knockbacking enemies aside and dealing those secondary enemies even more damage (based on the bonus health of the kicked enemy).
Not only Lee Sin's ult is more impactful than most of the aformentioned ults, but it also does more damage than all of them (except peharps Graves but that is only because he tends to build more damage oriented, if looking only at the base damage and the scaling then Lee still does more damage) on top of it having a lower cooldown at all stages in the game. This is significant, especially because Lee Sin has an easier time stacking CDR than ever (Warrior + The Black Cleaver, peharps adding CDR Runes or a Maw of Malmortius, with that he can reach 40% CDR).
I don't understand that. I get that Lee Sin's ult is going to be nerfed (there are nerfs on the PBE if I am not mistaken) but it is still not enough. Why doesn't Riot increase the cooldown on his ult just to bring it on par with other jungler's ults?