@Izabela
the duality is exist in her pair of programs SP AND FS since beginning, always some contrast in her pair of competitions programs although connected in other ways. but her later programs such as Kiss of Vampire etc. the duality is within one program itself, and it became more and more prominent.
In SITC, Yuna said in interview she wanna express "the bitter and sweet" and Adios Noinion really is a very complex mixed feeling interpretation, even more than just two. exactly like old wine.
to expect one skater, be it is Zijun or Korean Youngster or Wakaba etc. to be the heir of Yuna is not only unrealistic nor fair to the particular skater. The important thing is Yuna's philosophy of figure skating, inspired and influenced skaters (but not who is the next Yuna). And it is indeed deeply rooted in many new generation skaters. but unfortunately, ISU seems do not particular appreciate or understand the philosophy of Yuna's skating, especially in the artistry department, Thus we can see some spirit in e.g. Wakaba, but she is the minority here. The component score direction ISU currently is pushing is not what Yuna represents. Skaters need to follow the rules. but I believe Yuna's influence is deep although it may not show much at the moment.
about Giselle, in this summer break, I may translate an analysis I wrote years back about this program (in Chinese) and posted it on GS, there will be more details.