The 25/12 (and all Chopin's etudes) is one of those pieces that tests the pianist's limits. About VL's performance, she played it very "safely", if you know what I mean.
Yes, I believe I know what you mean. But I find that most pianists who go for anything "complete" - whether it be all 27 Chopin Etudes (or just 24, or 12), or the complete Chopin works for solo piano, like Ashkenazy did - there are always sacrifices/compromises that are made, where some pieces get the love and attention they deserve, while others are only given the attention necessary to make it through the piece. So, I guess I feel like this one wasn't really loved by either Lisitsa or or Ashkenazy, at least by the recordings I've heard.
There were some recordings that Ashkenazy greatly improved from the "Complete" publication to the "Favourite Chopin" recording, though, especially the B-flat Minor Sonata. Aside from what I feel is excessive liberty with the tempo, that recording of that sonata is probably the most impressive I have heard. The recording from the session that was used for the complete publication was only decent in comparison.