According to Riot Mortdog, excluding Warwick, the Champion Cores in Teamfight Tactics Season 9 are currently in an extremely weak state.
In Teamfight Tactics Season 9, Riot Games introduced some Technological Cores to alter gameplay or enhance the strength of certain champions. Therefore, players in League of Legends often humorously refer to these core types as Champion Cores due to their similarities with the Season 8 mechanics. Riot anticipated that these upgrades would result in unique gameplay styles.

However, the reality reveals that most of these Champion Cores are currently quite feeble. This was confirmed by Riot Mortdog, the Project Director of Teamfight Tactics, stating that only Warwick remains adequately powerful. Meanwhile, upgrades for Sett, Kassadin, Swain, or Galio are falling short of expectations.
'Based on the data we've collected, Warwick's Champion Core proves to be the most effective. In contrast, upgrades for Swain, Sett, Galio, or Kassadin are all in an extremely weak state. Their win rates and pick rates are at an exceptionally low threshold. Perhaps the value they bring is too meager, and the team will seek ways to address this,' shared Riot Mortdog.

Fundamentally, Warwick's Champion Core is effective due to the inherent strength of the Challenger System. In contrast, the remaining champions do not benefit from this preference, resulting in the significantly limited effectiveness of their Champion Cores. Take the case of Kassadin, whose own strength has considerably diminished after the Cantrips system nerf. As a consequence, Kassadin's Champion Core is also considerably weakened.

Certainly, the idea of pushing some 2-cost champions to the forefront with Champion Cores is not bad at all. However, Riot Games seems to have made somewhat unreasonable choices or not granted enough power to these upgrades. Hopefully, with the upcoming patch 13.14, Riot will make adjustments to make the upgrades of Sett, Kassadin, Galio, and Swain more impactful.