Agreed, ambiguously named form input fields cause all kinds of havok, I helped our UX team track down one in our application because it was breaking my lastpass =)
For the second issue, I've just adjusted my workflow to accommodate LastPass's peculiarities. I just click "Generate Secure Password", copy it to the clipboard and fill the form myself. Then I have a copy of the password on the clipboard should LP miss adding the site properly.
While it's a slight pain to work around that particular issue, it's far better than what I used to do with regards to password reuse.