What else do you want from the best healer? Let her be a one trick pony that keeps you alive no matter what.
Because based on the other healers, they all do at least
something else, or at least do a great job at applying their element (Barbara). If Qiqi's cryo applicator skill got a buff, that's at least something. Let it last longer, proc more often, and give energy particles. That's enough to make her at least considered for a team slot. If you think she's fine as is, how often do you use her in your party? I'd suspect never. That's the problem, there's never a good reason to include her.
Healers honestly took a big hit in necessity when Zhongli and Geo got buffed. You just don't need that level of heals for anything. Healers that also do other things like Bennett, Noelle, even Diona can not only heal, but also generate energy, shields, atk buffs, etc. Hell, even Ningguang with a Prototype Amber is more useful and deserves that team slot more than Qiqi.
Then you have Jean who is (IMO) one of the best designed characters in the game. She has heals on her autoattack at 50% chance, she has a huge burst heal that also cleanses and damages enemies - which lasts a decently long time. Her heal gets everyone in the party regardless if they're on the field or not then the AoE constantly heals and cleanses AND pulses damage if it cleanses an element, in addition to doing damage anytime an enemy passes the threshold. She has a unique charge attack that floats enemies (a viable CC method for small annoying enemies), she can toss enemies into things (which also swirls), and cause fall damage which can exceed damage for any other sources if the enemy has enough HP (since it's % based). Then you look at her constellations and she gets stuff like boost on her yeet skill, the ability to increase party movement and attack speed after collecting a particle, increasing def for the whole party etc. On top of that she has excellent energy generation and can universally fit into a team.
Tell me after looking at her kit and constellations that Qiqi is fine. I would say it's just usual power creep but Jean and Qiqi were both already in the game from day 1. I don't understand how the character design team looked at those two next to each other and was like "yea this seems right".