I wouldn‘t say I completely agree with this. Aliona is better than most of them but I think we shouldn‘t forget Nastya Tarakanova. I know she‘s kind of going through a difficult time with all the coaching changes and while she‘s not as refined and elegant as Aliona, she‘s faster than her and her edgework is of the same quality. So, I‘d put them on the same level, if not even Tarakanova a bit ahead. Kanysheva also has nice edges but she‘s a bit slow. I haven‘t watched Sinitsyna often enough but from what I remembered, she had pretty good skating skills too. Panova seems to do something right here, it seems. But yeah, overall, Tarakanova and Kostornaya clearly on top.
As for Aliona vs. Evgenia, I think that‘s fair to say. Evgenia has put in some real work on improving her skating skills with Tracy but her edges aren‘t as deep as Aliona‘s and she‘s also slower. So, yes. I agree. Personally, for me performance is the aspect where Aliona can improve because while she‘s a very musical skater she isn‘t as emotive yet and her facial expression doesn‘t change at all throughout the program. I‘d say Alina but especially Evgenia who‘s known for emotional performances (miming, anyone?

) are ahead of her in this aspect. Aliona definitely does beat both for me in the transitions part, though, at least with the way their programs were constructed last year. Evgenia basically had a lack of transitions so that‘s not comparable anyway and while Alina does dozens of them, I feel like Aliona‘s are better executed. They look easier and cleaner and not as rushed. It will be interesting to see how their programs will look like this season because Evgenia CAN add some transitions and Alina CAN perform hers better if Daniil allows her to breathe a bit and hold her moves. So, as for now I put Aliona ahead of Evgenia in the skating skills and transitions category while Evgenia beats her in performance. They‘re about even in interpretation even though I would put Evgenia slightly ahead here but that‘s pretty subjective in this case and it‘s also a small margin. As for Aliona and Alina, Aliona wins again in skating skills and transitions and also slightly in interpretation because I feel like she interprets the music with her body better than Alina does. Alina is ahead of her in performance, though because while she‘s not the most emotional skater, she can show a bit more variety than Aliona did so far.
I really tried to be fair and objective here but I guess everyone will be a bit biased for their favorites in something like PCS that‘s not as clear cut as - let‘s say whether a jump should get positive or negative GOE. (And even that‘s quite the challenge sometimes lol)