Currently BNB is the most potential altcoin to replace ETH as the king of altcoins, but replacing ETH as the king of altcoins will not be easy because currently BNB's market capitalization is far below ETH. currently transaction fees on the BSC network are the lowest and currently many new projects are opting for the BSC network, besides that BNB/BSC is also supported by the largest exchange called Binance. with that reason why I say that BNB is the most potential altcoin to replace ETH as the king of altcoins.