The idea is fascinating but the "exotic matter" required is something that can produce negative gravity - that is, expands space-time instead of contracting/curving it.
So you would have regular ol' gravity in front of you contracting space and negative gravity behind you, expanding space.
It would push you forward, despite the fact that you aren't really moving relative to space; just the bubble of space itself is moving.
Some new calculations showed that it doesn't require nearly as much energy as anyone thought to move objects though, of course, the idea of negative gravity thus far is completely ludicrous.
This is probably our best bet for FTL travel within the next 200 years or so. Traveling via wormholes seems even more problematic - equally exotic matter is needed to stabilize them. Plus, in my view, you would need to have already visited a point in space you wanted to tunnel to. So you could create highways for later explorers, but you couldn't explore with that technology.