I think Serge's back was only weak in the sense that he may not have known how to pose it to its fullest. There are a bunch of pics of Serge showing quite a strong back development. His calves were well proportioned - not huge but not all that small either. If they were any bigger they'd probably have made his thighs look smaller, reducing the proportion of his physique.
Serge had incredible strength's in his physique that looked phenomenal from various angles.
We will have to Agree to disagree
He had some good bodypart &
Looked good in those angled / twisting shots only
Calves / Legs / Back Thickness we’re not his good parts at all.