One thing to think about from a design perspective is the scalability of fast hellos. If you have a router with several hundred interfaces, each sending subsecond hellos, the RP has to process a lot of hello packets. If you can design your network to have point-to-point interfaces, the interface flap will most likely be quicker and a more scalable way of detecting failures. If you can’t do this you may want to look into Bidirectional Forwarding Detection (BFD). BFD is protocol independent, so it can signal multiple interface protocols in the event of a failure.
References:
BFD
OSPF Support For Fast Hello Packets
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