Well. This could be a game changer. New Warp Drive theory

[Vitto]

I am not optimistic about the development of any meaningful superluminal drive.

Partially because I somewhat doubt the physics of negative energy and none of the candidates for types of exotic matter that I've heard about seem likely to be possible for us to design with, build with, contain, and use.

Partially because the speed of light seems to be a fundamental limit on causality - the rate at which any energy can change anything distant from itself.  And I believe in a fairly strong causality.  OA with its notion of wormhole mouths created by entanglement and then moved apart through realspace, with preservation of the Vissier limit on propagation of change, seems (barely) plausible to me.  An out-and-out superluminal drive that can be used to go in any direction does not.

But mostly because of how much more horrible it makes the Fermi Paradox.  I can buy the notion that we're alone in this galaxy, or alone in the nearest 200 galaxies.  We literally don't know how long the odds were.  But if you now introduce a superluminal drive, and aliens at least as smart as us who can use it, we suddenly have to explain why we're alone in countless millions upon millions of galaxies.  

All those places where life could have arisen is one thing without a superluminal drive.  But if there is one, then we have to consider places where life could have arisen anywhere in the universe, because if they have arisen and discovered a superluminal drive we'd have met them by now.

Well, one possibility is that FTL drives cannot be arbitrarily fast. Star Trek, for example, has a definite speed for warp travel. Various instantaneous-jump drives in fiction have proportional errors in destination coordinates, and punishing computation requirements that limit effective travel speed.

Say your FTL drive will let you "travel" at a pseudo-speed of 1000c. That gets you to Alpha Centauri in a few days, but the Andromeda Galaxy takes 2000 years. And the Virgo Cluster takes 40,000.

Also, I presume, all of the proposed "serious" FTL methods assume that debris aren't a problem. If they are I guess that going FTL is gonna be tricky, to say the least.