I wanted BGP to pair my physical network with a Kubernetes cluster running Calico networking (no IPIP, VXLAN, or NAT required). On my current 6610, not only did I get this working in about 15 minutes, but I was able to redistribute the routes to other parts of my network via OSPF. Basically all of your cluster IPs are part of your normal infrastructure, allowing you to set policy both within the cluster and at the network layer. It's pretty cool.
When I drop this to a 6450, I've decided to just do router-on-a-stick with a Mikrotik RB4011, which on its single SFP+ port can route 10gb/s on that one port (I've tested it) and supports BGP. I'll then have it redistribute the routes via OSPF to the rest of the network, which the 6450 will manage. All of my nodes have a separate interface to my storage VLAN, so that won't hit the Mikrotik, so the Mikrotik will really only be routing traffic that enters/leaves the cluster...and 10gb/s should be plenty enough for this for me.
That said, BGP support in the 7250 or 6450 would have eliminated a device and some complexity. The 6610 is incredible and is less than 40db from the next room, but it draws too much attention from the wife when she enters that room (~55db), so this is my current plan... though there is a part of me thinking about trying to swap in a rev b power supply. It would be good if someone can post noise measurement of a 6610 operating with one of those... I feel like I'm just at the borderline of acceptability.
Clayton