Good lord there are walls of text above me! Let's see if I would ended up in similar conclusion like you guys or not. Too bad Hunter doesn't join us here since I think he has Red Ginger too. Note that this is just paper verdict since I don't have her and my helper rarely use her.

Red Ginger is the first 6* with single target and drain effect in one. So naturally back then they need to balance things out and...

1. Raw stat: Her stat would suffered and it just has to be her atk that suffered. It doesn't reach even 7000 but in exchange her hp is nice with 21600, goes well with her skill. Def is average, not too high or low but for girl with counter ability, it's definitely not enough.
Grading: C

2. Skill: Now we're talking. Her skill is 4.2x and drain HP. High activation rate with 36% top and considered her ability set, it definitely worth to get her skill level to 5 unless you have waifu priority rather than usage. Her skill also help increase her max HP even further with healing boost promotion ability. Her HP can reach as much as 27000 max.
Grading: S

3. Abilities: What a mix bag of one. But this bag is definitely worth owning and using. 30% atk boost, 15% skill damage, and 1.36x skill act combo work together nicely to maximize the damage output for your team and herself. A bit expensive with 4 rainbow skillblooms for max potential but I think it worth the effort. The synergy of these 3 is top notch in its category, the damage. However the rest two are not so appealing. Counter is mediocre at best since her def is also mediocre and speed +150 is a make or break for the team. It can salvage team speed or disable the brake and her team will rush to the goal while the other team barely a step away from the last pest node. Not really helpful unless on specific team build or map.
Grading: A-

Final verdict: A She's solid unit but suffer from bits of bad skill synergy and stat to reach S pinnacle. But definitely a solid unit to have since she can support very nicely and under proper support, she will dish crazy damage while refuse to yield.

Extra: *note that my extra is not always about waifu factor, it can be any kind of personal opinion, the more subjective view towards the girl*
It quite a baffle to me why she's not popular, like not at all in helper team/ Japanese players and it reflected in polls. Gameplay wise she's not as broken as Kerria despite how similar they played? Waifu factor Japanese not a fan of tall, tanned girl? I think she's pretty fine, not as much as Shad level of dedication but solid enough.

Extra 2: I have a request to Shad and Wutan (and Hunter if you guys bother to read this far) Can you form a team around Red Ginger, it can be any archtypes you think she's the strongest with your team. Then fight lv.90 raid boss with 18m HP, then post how much damage she can dealt in tactica? I want this thread to be tier discussion only. It MIGHT answer my question in extra 1.