Too early to tell.
The universe is constant, no wait, it's expanding, so... Dark Energy!
Well, wait a minute, it's not expanding as fast as we thought, so.... Dark Matter!
Oh shoot, now it's expanding faster than we thought, so... Dark Energy 2: The Darkening!
I think it's time to admit we don't have such a good idea about what's going on, and re-evaluate ALL our assumptions on the matter (no pun intended).