The issue is gp is hard to balance between regular play and meh LCS!!!!!
He's a relatively uninteractive champion (yes he spams Q on you, but you don't actualy clash very often). Who wins through scaling like crazy.
But compared to other global or near global ults, his has several advantages (others obvs also have advantages over him as well )
Gonna use I.C for instant cast and I.A for near instant arrival
Compared to:
: gp hits multiple people, can deal more dmg, I.C, I.A
I.C, I.A, deals dmg
cc, I.C, I.A
can be cast anywhere, i.c i.a
i.c i.a cc
i.c i.a cc
i.a cc multi target
i.c i.a dmg. Multi target cc
dmg, cc I. A i.c
cc,
cc i.c dmg
i.a cc
As you can see. Instant cast and a lack of travel time is the common advantage.
This makes it stupidly strong to initiate fights elsewhere or to save people (as it isn't almost global, it is fully global).
While the cc isn't very strong. It allows team mates to land their follow up cc easier.
It isn't meant to deal allot of damage. It being off cd applies pressure everywhere on the map. And unlike most other globals, it can be used for emergency waveclear since it hits everything.
Sorry babe. But it's just hard to buff him cos riots lcs. And because it's unique advantage gives it a significant edge over other globals.