Is it permissible to dislike praying behind the current Imam and demand his replacement, given his weak memorization and tajweed, his repetition of surahs, his frequent mistakes during Tarawih, and his failure to fulfill a guiding role in the mosque?

If the Imam makes errors in his recitation (lahn), changes words and vowelizations (harakat), and recites too quickly, then his imamate is indeed disliked (makruh); because his errors may invalidate the prayer if they alter the meaning in Al-Fatihah. The imamate is a weighty matter, and the most deserving of it is the one who is most proficient in reciting the Book of Allah. The jurists have stipulated that it is disliked for an Imam to lead people in prayer if they truly dislike him, and a severe warning has been mentioned regarding this. It has been reported that the prayer of an Imam whom people dislike does not ascend beyond their ears, and that the one who will receive the severest punishment on the Day of Resurrection is an Imam whom people dislike. The matter should be brought to the attention of the responsible authorities to replace the Imam with another who meets the required conditions.