In previous titles, the best one i can say is Tag 2, Asuka is more a defensive character with reversals whereas Jun is more mixups oriented with reversals.
Both Asuka and Jun do have punch sabaki, f2+3, and a mid/high reversals, b1+3. The difference is Jun “cannot hold her reversals” unlike Asuka.
They are both annoying and frustrating to play against due to full of “knowledge checks”.
Jun has more options to open her opponent but Asuka struggles in opening of her opponents.In the end, both characters share same and similar tools, therefore both considered very similar.
However, In Tekken 8, their entire character chemistry changed. Asuka has become a full “gorilla” character with great Offensive Tools like wr1+2, NWG Install and the infamous uf1,2, AHO BOKE.
On the other hand, Jun gets more stances to mix their opponents. Her new Install boost her damage and increases her laser, MIA 2. This stupid move can hit her opponent from Range 3 to 4 and can be safe due to distance despite of being -20. MIA 1+2, B1+2 1+2, is a homing move and create a true RPS. Furthermore, this move can reach her opponent from Range 3.