Q: 180 (+50% AP) on 3s CD
W: 250 (+75% AP) on 9s CD
E: 180 (+30% AP) shield on 9s CD
R: 300 (+70% AP) on 90s CD
idk these are very respectable numbers, not to mention that you get an AoE speed-up/slow and a shield that gives bonus resistances. that, and one of the best teamfighting ultis in the game. she's probably low win-rate because she excels in a coordinated team environment, which you're not gonna find in clown fiesta NA soloQ.
for reference, here are the champs u mentioned below
Sona:
Q: 200 (+50% AP) on 8s CD
W: 165 (+30% AP) max heal on 10s CD
E: no damage or heals or shields
R: 350 (+50% AP) on 100s CD
Karma:
Q: 260 (+60% AP) on 5s CD / 525 (+90% AP) total magic dmg, share CD with R
W: 260 (+90% AP) on 12s CD
E: 200 (+50% AP) shield on 8s CD / 410 (+80% AP) shield, share CD with R
R: empowers other abilities
Janna:
Q: 265 (+65% AP) max damage on 10s CD
W: 280 (+50% AP) on 12s CD
E: 240 (+70% AP) shield on 10s CD
R: 600 (+150% AP) total heal on 120s CD
I don't see where this "amazing AP scaling" is that Ori doesn't have...