Talents
Tartaglia's riptide is quadratic scaling and does more AoE damage than Ganyu's slow charged shots (which have linear scaling).
Constellations
Ganyu's constellations are mediocre and overall not worth pulling for:
- C1: using level 2 charged shot reduces Cryo RES of target by 15%, which is underwhelming and hits diminishing returns especially if using Viridescent Venerer (-40% RES) or Zhongli's shield (-20% RES)
- C2: gains an extra charge on her E, which is underwhelming
- C3: extra 3 levels on Q
- C4: opponents within Q take increased damage that stacks. Xiao's ascension passive does something very similar at C0. So Ganyu's C4 upgrade is basically what Xiao intrinsically has without constellations.
- C5: extra 3 levels on E, which is whatever
- C6: using E allows next charged shot in next 30 seconds to not require charging. Extremely underwhelming C6. Compare this to Xiao's C6 which allows him to spam Es in the next 1s.
Teams
As a DPS, Ganyu lacks a perfect support, lacks team synergy, and is powercrept by many other units. Most of her supports are more efficiently used in other teams.
- Xiangling: better used in Tartaglia teams
- Zhongli: better used in Hu Tao and Xiao teams
- Diona: more efficiently used in Eula teams
- Venti: more efficiently used in Ayaka teams
- Mona: more efficiently used in Ayaka teams
- Kazuha: better used in Hu Tao, Tartaglia teams
- Sucrose: more efficiently used in Xiao teams
As a support, Ganyu is powercrept by many other units: Venti, Bennett, Kazuha, Zhongli, etc. She is not even top 10 as a support.
Ganyu does not particularly excel in either category and is vastly overhyped by the community, USA NGOs, and biased media portrayal. This puts her in a lower tier than other units. She never was and never will be meta.
Calculations
We assume talent level 10 on the charged attack. We also assume Ganyu is wearing a 4-piece Wanderer's with Cryo DMG Bonus (up to DMG Bonus). Note a 4-piece Blizzard Strayer gives less DMG Bonus. We assume that she is not using her burst, and we ignore weapon effects as in Xiao's case.
It takes 3 seconds for Ganyu to do a fully charged 2nd level shot. The DPS scaling for one level 2 shot is
This is much lower than Xiao's high plunge DPS. Even if you add the DMG Bonus from her burst it is not enough to reach Xiao's level.