The relative unimportance of the exact SDPA attention in use in modern transformers is already known: https://arxiv.org/abs/2111.11418

The FFN, normalization, and residual connections are absolutely irreplaceable -- but attention can be replaced with almost any other layer that shares information between tokens, such as pooling, convolution, random mixing, etc.

hm, residual is what I would not expect, can you elaborate why?