[touche_bag]

Huh? Rerank is always a boost on top of retrieval. So regardless of the chunking method or model you use, reranking with a good model will always result in higher MRR. And improvements in embedding models also will never solve the problem of merging lexical and vector search results. Rank/score fusion are flawed since both are hardly comparable and boosting only works sometimes. Whereas rerankers generally do a pretty good job at this. Performance is indeed the biggest issue here. Rerankers are slow as hell and simply not feasible for some use cases.