Performing the following (note the range of 10,000):

`importmulti '[{"desc": "sh(wpkh([aeee1e6a/49h/1h/0h]tpubDC5bVdaveQYxGFztMShFAjU637kKjrs9FD8ne1oHR7z8tLeQJExsaxWRVeSpcCcYMdp5ecf2LQhuVaeYFZ7YEpvWTJr4nDGUJrmuvLuTSsp/1/*))", "keypool": true, "timestamp": "now", "watchonly": true, "internal": true, "range": {"end": 1000}}]' '{"rescan": false}'`

takes many minutes. @achow101 reports a similar import taking 6 minutes on his machine.
{
    m_script_metadata[CScriptID(dest)].nCreateTime = create_time;
    return AddWatchOnlyWithDB(batch, dest);
}
bool CWallet::AddWatchOnly(const CScript& dest)
{
    WalletBatch batch(*database);
    return AddWatchOnlyWithDB(batch, dest);
}
bool CWallet::AddWatchOnly(const CScript& dest, int64_t nCreateTime)
{
    m_script_metadata[CScriptID(dest)].nCreateTime = nCreateTime;
    return AddWatchOnly(dest);
}
bool CWallet::RemoveWatchOnly(const CScript &dest)
{
    AssertLockHeld(cs_wallet);
    if (!CCryptoKeyStore::RemoveWatchOnly(dest))
        return false;
    if (!HaveWatchOnly())
        NotifyWatchonlyChanged(false);
    if (!WalletBatch(*database).EraseWatchOnly(dest))
        return false;
    return true;
}
bool CWallet::LoadWatchOnly(const CScript &dest)
{
    return CCryptoKeyStore::AddWatchOnly(dest);
}
bool CWallet::Unlock(const SecureString& strWalletPassphrase, bool accept_no_keys)