Some comments from @sipa in #12702.

___

Yes, I think `importmulti` is superior in every way, except:
* Slightly less convenient to use (it requires redundant information, as you have to explicitly state what you want to import, and then give the keys/... to enable that).
* ~Doesn't support P2SH-P2WPKH yet~. Added in #14454

The latter can be fixed by just adding support for that case. The former can be improved by adding 'default' cases (e.g. if you prove a WIF private key, it can permit omitting the address, ...).

{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() < 1 || request.params.size() > 3)
        throw std::runtime_error(
            "signrawtransactionwithwallet \"hexstring\" ( [{\"txid\":\"id\",\"vout\":n,\"scriptPubKey\":\"hex\",\"redeemScript\":\"hex\"},...] sighashtype )\n"
            "\nSign inputs for raw transaction (serialized, hex-encoded).\n"
            "The second optional argument (may be null) is an array of previous transaction outputs that\n"
            "this transaction depends on but may not yet be in the block chain.\n"
            + HelpRequiringPassphrase(pwallet) + "\n"
            "\nArguments:\n"
            "1. \"hexstring\"                      (string, required) The transaction hex string\n"
            "2. \"prevtxs\"                        (string, optional) An json array of previous dependent transaction outputs\n"
            "     [                              (json array of json objects, or 'null' if none provided)\n"
            "       {\n"
            "         \"txid\":\"id\",               (string, required) The transaction id\n"