Soul and morality

1. What is the rabbi's position on the importance of 'correcting one's manners'? Does it have value in itself, is it appropriate to engage in it as a way to enable the fulfillment of the mitzvot?
(The Rev. writes in Shaarii Kedushah that correcting character traits is not a mitzvot at all, but they are means to the mitzvot, because a person who does not have corrected character traits does not have much self-control and will have difficulty fulfilling the mitzvot…
How does he explain Chazal's sermon on 'and walk in his ways'? (Rambam learns from this that there is a commandment to correct the virtues, but he apparently disagrees with him)… I thought that perhaps these articles deal with the commandments between man and his fellow man, that it is appropriate to adopt sensitivity towards others… in contrast to the Shaak, which speaks of virtues such as anger, pride that are related to a person's self-control, and not just means… (similar to Rambam's division into eight chapters, 16, although not equal))…
2. As a result of the above, in what ways does the rabbi recommend engaging in these? Mainly intellectual understanding, through practical practice, or even through the 'insight' and 'admiration' of the moral movement?
3. Historical question – The Mussar movement had some influence in the Jewish Torah world, but was generally not embraced. Part of the opposition to it stemmed from the introduction of studies beyond the Gemara into yeshivas. This does not seem to be the reason it was not embraced, but rather more principled arguments regarding the benefits of such an intensive engagement with the virtues…
Does the rabbi have any information or sources regarding that objection? What does the rabbi think about it?
(My tendency is to engage in learning and doing the right things. And when there is an area that is particularly difficult for me, I try to correct the tendencies that cause this, through awareness and practice… but while progressing through actions and not through 'digging')…