What do you mean? How are you measuring that? How do you think that would make a password of the same length and character set less secure in a practical way?
https://security.stackexchange.com/questions/77345/security-...
So it seems like LastPass-generated passwords are fine?
[1] https://developer.mozilla.org/en-US/docs/Web/API/Window/cryp...
The thing is, there is a chain of things you have to trust wrt the LP generator: Has the OS implemented the backend API correctly? Were there issues in the browser build that mess up the entropy derived from the OS seed? Has the Javascript done anything stupid?
In comparison, I have complete confidence in the entropy of the passwords I generate via CLI.
Wrt. password length: yes you can change it. But the dialog is a bit of inconvenience that tilts away from the hassle of switching to my terminal and typing "suggest-password". And I have something of a moral objection to password generators that default to insufficient entropy.