Hi Sascha,
The real solution is to have end systems handle session handover between multiple addresses it has, but there seems to be pitifully little traction for that.
I think we've been there (sounds a bit like SHIM to me), we'll see if that takes on. But i don't think such workarounds can replace BGP multihoming in all cases. But it can help to spare some people the hassle to deal with full BGP multihoming if don't really need to be in the DFZ, but just want some level of redundancy indeed.
Getting a good solution for this is _very_ important to limit routing table growth. Many people/organizations probably don't want the hassle of BGP if they can get more redundancy and less dependencies on a single ISP (easier renumbering will help too) in a simpler way. But this is IETF territory, not RIPE :-) Thanks, Sander