We have a very difficult topology.
We have 3 routers in different places where each have a VPN to our customers.
Our customers have more or less branch offices, home offices, external service partners and local partner networks.
Not every router knows the whole topology and will route unknown subnets in direction of the hub router.
Its like routing in a tree. If we have to optimize it we will make short paths.
In this situation there should be something like a big transfer network and every router should use ospf.
If a roadwarrior is added he will get a IP from this transfer network and get all routing information automatically.
At least this must be possible with multi wan at different bandwith, qos, load balancing and fall back.