I also think the preterite implies that the statement is still true in the present, or it was true until the moment in which she met the person. But, for instance, the sentence "Ela sempre queria conhecer pessoas novas nas suas viagens" (She always wanted to meet new people on her trips) implies a thing that belongs to the past, which isn't true anymore.
Does this make sense?
I probably wouldn't use the imperfect there (or I'd place the adverb somewhere else - don't ask me why or where, it may be an EP thing), but I did find an answer about the different uses of querer in BP. From Whitlam's Modern Brazilian Portuguese Grammar (p. 382):
When talking about the past, the imperfect of querer is used to talk about recurring desires or those that were unfulfilled, at least at the time referred to:
- Ele sempre queria sair com a gente. He was always wanting to go out with us.
- Nós queríamos conhecer Paris. We wanted to visit Paris. (i.e. that was our as yet unfulfilled intention at the time).
The preterite of querer refers to something that you have wanted to do or that you wanted to do and actually did:
- Ele sempre quis ser médico. He’s always wanted to be a doctor.
- Quisemos conhecer Paris. We wanted to visit Paris (and that’s why we went there).
Does that make sense to you?