Riot introduced a new scaling for support champions by introducing Utility scaling.
And that was the moment were mages used as a support
became legitimatly better supports than actual support champions like
.
That change also generally solidified Lulu as a solo-lane champion rather than a support.
For a champion to be a respectable support, you have 2 main jobs.
- Strong early-game presence. With a strong early-game you offset the weak early of many marksman, making a marksman+support combo make a wide range of marksman feel like extremely strong early-game champions.
One thing that really helps a strong early game is good bases, or rather: if you're looking at champions with strong bases and weak scaling vs. weak bases and strong scaling, the strong bases and weak scaling is exactly what helps here (exact opposite of a carry).
- Respectable late-game presence while being significantly behind in levels and items compared to everyone else.
One thing that really helps here is having...strong bases and poor scaling.
In both cases: having utility-heavy things like a 1.5 second stun be a 1.5 second stun regardless of what you itemize for and what level you are is really what makes a champion a good support.
The entire reason supports are high utility rolls ATM is also due in large part to most utility just not scaling with much of anything.
Add scaling to support champions: and because of balance, you're left with supports giving up early power for essentially nothing in return outside of a slightly stronger late-game if they're played in a solo lane.
And I mean: I like AD sona and AD Janna every now and then, but if you gate a lot of their power with items - the thing supports have less of than anyone else - those will be the only ways to reliably play such champions.
TLDR: making supports have good late-game scaling makes them poor choices to play as a support.