Once again, I almost forgot to rate a girl.

Pink Miko is S Tier. What? We don't speak about Pink Miko but Regular Pink? Okay...

Stats:
HP: Low HP, under the 20k. But she is not a defensive girl at all so, that's not a big problem for her.
ATK: She has the highest ATK stat from all the Natural 6* (with Nerine) with 8644. I'm pretty sure we can say she is good at it.
DEF: Pretty good defense. That's okay.
Low HP are always her weak point statwise. But ATK and DEF are good enough to compensate it.

Skill
2.9x damages to all, 34% skill rate.
2.9x damage is good but only x0.1 damage more than all the 2.8x for 34% rate instead of 37%... meh. It's not a bad skill at all but if she was in the x2.8 / 37% familiy she would be slightly better.
But that's okay anyway. Pink is Pink afterall.

Abilities
Okay let's start with her worst point.
Party members Heal 10% HP when encountering a Nest Panel
Useless legacy from olds times. No harder maps have encouterable Nest Panel. And you don't really need a solid 6* team for Event or Main missions.
Next ability please.

+25% ATK for all
That's, good. Not awesome but good. Most girls have +20 or +22%. +25% is slightly above. I'm ok.

1.28~1.36x skill rate
It's a rare ability and that's a good thing she got it. And that's why she would be better with a x2.8 / 37% skill instead of a x2.9 / 34% one.

+20% ATK on boss fights
That's good but not that much. But that's still welcome anyway.

+15% damages on bosses
Another good thing for her. It gives her a place in boss killer teams.

And... that's all. She is good but she still lack a little something to be better than good. I means, she had a totally useless ability and almost nothing to compensate it. All her abilities are good or very good but nothing awesome like some other natural 6* have (I don't speak about S Tier 6* obviously).

Team Build
With her nice ATK buff on bosses, her damage buff and her good skill act buff, she can be a good ally for boss killer team, or any other offensive archetype if you have a free place. But despite her assets, she is not a really a must have in a specific team out of boss killer (and even in boss killer team, she is a good girl but not an obligatory girl).

Conclusion
Pink is a good girl but less good than Pink Miko (in term of efficiency related to her amount of stars obviously). But she is not bad at all. Her good ATK and her boss killer assets make her a nice ally to have is most teams but she still lacks a bit of adaptability to shines in more than one very precise archetype.

Final verdict:
I wanted to give her a B Tier due to her lack of the little something mentioned above but I let her slip to the A Tier just because she is n°1 in ATK and almost all her assets go in tht way.
I like you Pink, but your Miko Version will always be higher in my heart