Galley Proof are the preliminary versions of publications meant for review by authors.
Question: To what extend, one should improve the article in Galley Proof ?
Situations 1. If all the proofs are fine, just modifying few typo error, and misprint would serve the purpose. But
Situation 2. Assume all proofs are fine. ( No change in proof anywhere. ) You receive a reply from Journal after a year. By the time, you realize adding few remarks from same or some other paper and citing the other paper could explain Article to some good extent. Should one add such remark and cite the other paper.