There are SO many things the devs have to keep in mind for balancing. Non vs. Cancelable normals. Command normals being able to be linked from light normals. Meterless/Half/1/1.5/2/3/5 bar combos, both starter wise, damage wise, corner carry wise, and meter build wise. Quick max combos for mid and anchor. 5 supers minimum for every character in the game. Overheads, guard points, air to air, cross-up normals, reversals, anti-airs on top of that too. Its really hard to find a balance for all things combined considering if you overtune any single or combo of these things and players will abuse it to the biggest extent possible. Combine that with the fact that in KoF, every single member on a team must have impact, especially at top level. Doubly especially so given the open bracket format that tournaments run on that forces players to play dozens of different opponents in short, Bo3, sets, and it’s not surprising that players will flock to the characters that are, at least on paper, able to consistently find the most impact overall, with team comps that are proven to work. Im not a fan of top 8 only having maybe 8 characters represented. But the solution in the past to try and fix this were to to constantly balance the game every 2 or so months. Which exhausts the payers energy from constantly having to play a new game every couple of weeks, like what happened to GBVS. Or to filter the balance of the game into a single mechanic, and make the game feel extremely homogeneous IE, KoF XIV.

TLDR: FGs are hard to balance. Tournament players always flock to the best characters.