The rapid advancement of generative artificial intelligence (AI) has transformed feedback practices in higher education, particularly in supporting university students' academic writing. Although previous studies have primarily examined the effectiveness of AI-assisted feedback in improving writing performance, limited attention has been given to explaining the pedagogical mechanisms through which AI facilitates sustainable writing development. This study aims to explore the pedagogical roles of AI-assisted feedback in university English classrooms, synthesise current evidence regarding its opportunities and challenges, and propose a conceptual framework for AI-assisted academic writing development. A qualitative library research approach was employed by analysing 33 scholarly publications published between 2017 and 2026. Data were collected through documentation and analysed using thematic analysis to identify recurring concepts and pedagogical patterns. The findings reveal four interrelated themes: AI-assisted feedback enhances linguistic development, supports recursive writing and revision, promotes feedback literacy and learner autonomy, and requires ethical and pedagogically responsible implementation. Based on these findings, the study proposes a conceptual framework illustrating that academic writing development occurs through the interaction of AI-assisted feedback, critical reflection, iterative revision, feedback literacy, learner autonomy, and teacher facilitation. The study concludes that AI should be integrated as a pedagogical learning scaffold rather than an automated writing solution, providing theoretical and practical implications for the responsible integration of AI into university English writing instruction.