CRS had problem of packetloss in case of loaded with high number of packets - handled by CPU.
You don’t have to do any strange things like EoIP or other tunneling.
http://forum.mikrotik.com/t/packet-loss-in-crs125-24g-1s/76451/1
http://forum.mikrotik.com/t/huge-packet-loss-on-crs125/85331/1
http://forum.mikrotik.com/t/crs-loss-packet/85704/1