We submitted a paper and got two rejections (from reviewers 1 & 2) and two acceptances (from reviewers 3 & 4) after the first round of revision. Now we have received a letter from the associated editor asking us to again revise the paper, and to include a response letter addressing the concerns of reviewers 1 and 2. Hence, the paper is not rejected or accepted.
We feel reviewer 1's comment to include a new case study is not reasonable, and reviewer 2's comment fundamentally changes the problem structure. We explained our reasoning in both cases in detail in our original response letter (especially in response to reviewer 1).
Is it reasonable to appeal to the associate editor at this stage (i.e., before rejection)?
UPDATE: The paper got published in the next revision. We took a middle path strategy: I wrote directly to the associate editor and briefly discuss my objections with the reviewer 1 & drafted my response letter to reviewer 2.