they are quite weak.
they were defeated by some genins
Sakon and Ukon did. It was very deadly. If Kabuto would've resurrected just one it should've been Sakon.Because they didn't have a kekkai genkai or a clan bloodline trait. They wouldn't have done anything really. Kimimaro is just one of a kind.
The main purpose of resurrecting previous shinobis were to attack the alliance emotionally and mentally. In that regard there was no reason to bring the Sound 4 back.
They had some unique techniques but we already saw them.
They weren't important enough I guess. I loved the Sound 4. Tayuya was my favorite.
I would've loved to see them and Kimimaro vs Jugo and Suigetsu, and during so, Jugo frees Kimimaro and then Jugo and Suigetsu beat the others.