rate limited, problem remains the same
OK, Reading the Asus source code, I successfully managed to limit MCS, turning the RT-N66U into 2x3 MIMO on 5GHz (wl1)
nvram set wl1_txchain=5
nvram set wl1_rxchain=5
nvram commit
reboot
Now, both MBP, the new retina and the old one, synchronize...