I think it's handy that some ports can be grouped together as a switch group and thus not put any load on the CPU as bridging would. It kind of depends what the switch chip would be capable of in regards to VLAN's and such, but judging from the RB2011 for instance it's at least possible to do it right.
It also depends how big the interlink between the switch chip and the CPU is internally, but most often this is limited to 1Gbit (a 5 port Gbit switch in reality with 4 ports external and 1 port internal). Hoping to see a block diagram soon. Actually, judging from the TILE-Gx8009 spec sheet, it has up to twelve 1000Mbit ports and/or 2 10Gbps XAUI ports + at least 10 PCIe 2.0 lanes.
Depending on configuration, it's possible that that the 4 Gigabit Ethernet ports are directly connected to the CPU, the SFP+ slot uses one of the 10Gbit XAUI ports and the internal switch is a 10Gbit internal uplink and 5x external Gigabit Ethernet ports model (including the SFP slot). This would impose no bandwith limitations if used as routed ports but would give you the advantage of being able to use them as switched ports, offloading the CPU.
Alternatively the switch or a 10Gbit port could be connected using some form of PCIe interface of which the processor also has a multitude available. Using the available 10 lanes of PCIe 2.0 bandwith that would result in 10x512MB/sec = 5120MB/sec up and down (full-duplex). More then enough to use for the switch or a 10Gbit SFP+ port, etc. That would still leave another 2 PCIe 2.0 lanes unused also the spec sheet lists that everything else such as UART, USB, etc. is separately connected.
Only time will tell, hopefully they will release a block diagram before it's purchasable so we can check out how they configured it before buying!
Personally I'm wondering what the expected NAT throughput would be. Sadly, I seem unable to find any real performance numbers for the other Cloud Routers thus I'm unable to make a guestimated number either. Does anybody have any numbers or tests on it? I'm hoping it will be able to do 1Gbps of NAT without too much trouble, making it a great router for newer fiber connections.