(Thinking mainly of eqiad/codfw here)
The way our VRRP setup currently works is that one of the two core routers (say, cr1) is the VRRP primary (previously known as master) for all VLANs, and the other one (say, cr2) is the secondary. The two routers iBGP & OSPF with each other and other routers in the network. Depending on eBGP AS path selection and OSPF weights, traffic may go cr1->cr2->{external to DC} or cr1->{external to DC}.
We could consider adjust the VRRP priorities to split VLANs between the two routers -- say, cr1 is primary for rows A/B and cr2 is primary for rows C/D.
The upside is that this would provide some natural loadbalancing between multiple paths both internally (e.g. codfw->eqdfw, eqiad->codfw), and externally in the cases of equal cost AS path lengths e.g. 1299 174 on one router, 2914 174 on the other. In turn, this means that we'd always exercise paths (such as e.g. a wavelength, but also cr->switch) that today remain idle until a failure happens.
The downside (that I can see so far!) is that it may make network issues more spotty and harder to pinpoint, as the return path may follow different paths depending on the server one accesses. Traceroute to the Gerrit box may end up being different than the one to the bastion host, as an example. By extension, for loadbalanced services, this will depend on which realserver the loadbalancer picked, which in turn would be a property of source IP (due to source IP hashing), so two different users even in the same ISP or /24 may end up having a different return path.