I was going through the up for grabs PR, and got interested in working on this but, bitcoin locked and limited conversation to collaborators 2 weeks ago, so I couldn't comment directly there.

Based on the previous discussions, here's my understanding of what needs to be done (if the change is still relavant) :

Keep the existing vsize field as the sigop-adjusted size and the new vsize_bip141 field to clearly represent the BIP141 virtual size (non-sigop-adjusted)for mempool-related RPCs.

Add optional sigopsize (sigopsize = nSigOpCost * bytes_per_sigop, please correct me if am wrong) getrawtransaction transaction when the transaction is in the mempool and the data is available.

Write additional documentation under doc/policy/ to explain the different vsize definitions, fee rates, and mining score heuristics.

Thanks!!!