It looks like she can be the next "dominating" rider in women's cycling, in case the women's scene does not get very broad and specialized. Who do you (Libertine?) think could challenge her?
Cille's problem will likely forever be that lack of a sprint weapon. At a similar age to Cille is now, Anna van der Breggen had very little sprint ability and really worked on it, to the point where she's "ok" now. Niewiadoma has been working on her sprint for a couple of years now with limited real results; Cille is starting from a position of real weakness in that respect which may hamper her results as long as flat to hilly racing remains the staple diet of the women's péloton, which may put her into a similar kind of position that Elisa Longo Borghini is in. Then again, if she ends up with a similar palmarès to Longo Borghini's she could probably retire happy (well, taking into account that Cecilie is almost always a bundle of energy).
If van der Breggen is shortly retiring, then I can see Cille becoming a real fixture of the winner's circle for punchy finishes. Van Vleuten and Moolman-Pasio are both 35+ at this point and though both started late and have fewer miles on the clock than a comparable men's pro as a result, this will be a factor and their time as pre-eminent climbers will eventually fade, and might already be doing so in Ash's case where she was being outclimbed by Pauliena Rooijakkers, who was cast free from domestiquing for her, at the Giro. We do have to be mindful of attributing too much value to this year's racing however, because of the differences in training capabilities of various riders in lockdown, but nevertheless, she has proven herself to be a truly elite puncheuse this year and somebody who is better the steeper the races get. We must also remember that there are a number of latecomers to the sport for women and this can also impact our expectations; in addition because they broke out really young we must also remember that riders like Longo Borghini and Niewiadoma aren't exactly old - they're 28 and 26 respectively - so they could well be around for a good few years as rivals in the stage races for Cille. In the one day races, then at present especially tactically then unless the climbs are really steep and long enough to put them on the back foot, there's still Vos and Deignan, who are 33 and 31 respectively so still have some time at the top left in them so long as they want it, though naturally you'd expect Cille to still be going strong when they retire. In the stage races there's also Amanda Spratt, who will be getting her first chance to truly lead for herself next year, and recently turned 33 too so she'll be a challenger for the next couple years at least.
Two names that immediately spring to mind for the future in the same kind of races as Cille would be targeting are Demi Vollering and Liane Lippert. Both have better sprint weapons than Cille; Vollering also has won the Giro dell'Emilia, albeit less decisively than Cille, and was on the podium on the Mur de Huy this week, so that kind of gradient clearly doesn't bother her. She's still only 23 and is moving over to SD Worx (Boels) where she will perhaps lead less, but benefit from greater support than Parkhotel Valkenburg can give her. She doesn't seem as explosive as Cille, but it's also hard to tell whether on that finale it was her tactical naïveté (she's also paid for leaving time gaps in front of her in a couple of stage races last year) and she ran out of gas too early or if Cille just had the climbing edge on her, or, most likely going from Demi's interview post-race, a little from column A and a little from column B. Lippert is younger still - 22 - and this year - admittedly a bit inflated by the exaggerated importance of the Australian offseason races with so many of the European races through the middle of the season cancelled or postponed - has moved toward the premier end of the péloton. She doesn't seem quite so durable as Cille as of yet, but she does seem good at riding climbs to tempo if she can't go with the pace of those at the very front. Most of her best results are in those punchy one-dayers and I'm sure she'll learn from the chastening experience of blowing up in the Women's Tour last year.
In stage races, other than established names we already know all about like Niewiadoma and Longo Borghini, the obvious name to drop here would be Mikayla Harvey after her stunning Giro. Again, have to be mindful of attributing too much value because of the differences in training etc., but the young New Zealanders have been flying post-lockdown and none more eye-catching than Harvey. On the 12,5% slopes of the penultimate stage of the Giro, she was able to go with Anna VDB and Elisa Longo Borghini when nobody else could and though she was subsequently distanced, she plugged away limiting her losses and was never caught by the likes of Kasia and Cille either. She had shown glimpses of real promise last year but this year has been way above and beyond expectation. She did win an ITT in 2019 also so she has the all-round skills (albeit that was impacted by Cille having a mechanical which cost her the GC).
Elsewhere there are people like Aalerud (25) and Merino (26) who could be intriguing challengers when it comes to the climbs, but I don't think are multi-dimensional enough at this point to be real challengers across the board, although they will likely get to learn from Annemiek van Vleuten next year, which will surely help. Paula Patiño likewise, she's 23 and a pocket-sized Colombian grimpeuse, she just finished top 10 of the Giro but that was largely thanks to the final day breakaway. Likewise Évita Muzic, who seems very promising as a climber and comes from CX so has plenty of all-round skills, she will likely graduate to be a second-in-command for Cille in the near future however, and perhaps fulfil the same role for Uttrup that she herself once did for Ashleigh Moolman-Pasio. Juliette Labous over at Sunweb is probably the most GC/climbing-oriented of their young riders, at least for races like the Giro, will be interesting to see what happens next year though as it seems Lippert's progression has rather trodden on her toes a bit, but also Sunweb having signed Lorena Wiebes might mean they put less attention on their climbing corps, and while Lorena Wiebes is definitely a star in the making, she can't really be considered a contender/challenger to the likes of Cecilie because they're completely different types of rider.
I know I'm going to post this and then facepalm completely about somebody I've forgotten, too.