Which is correct:
She is even nicer than I expected/had expected
or She is even nicer than I've expected?
We use a past or past perfect form, not the present perfect, to correct an incorrect belief or expectation, or to confirm a correct one:
She was just as beautiful as I have imagined./ She was just as beautiful as I had imagined.The area is wilder than I have expected./ The area is wilder than I expected/was expecting.