Technically, we do have some things knowing of so-far.
We know that the replacement will be atleast from what it seems, something similar to Terminator 2 in that it uses live actors, effects, and screen-based imagery.
We also know they are having to expand the armory, which will possibly mean that there may be more actors involved with this show than T2's 5 characters, John, Sarah, T800, T1000, and Kimberly Duncan.
And that there are two IP's that are more likely than anything so-far. Those being the 007 *James Bond* Franchise and the Bourne franchise.
Bourne, is more likely out of this, because it seemed to be more relating to if Universal could get the rights to use the characters for the films (and possibly as rumored, a show), but from what we can see; Annapurna is most likely getting the Film rights, which would leave Universal in the Bourne franchise.
And just because it would be Bourne, it doesn't mean that it has to be the Matt Damon character. In all reality, I actually could see them pull stuff from Bourne Legacy and some elements from Jason Bourne to spin it off into a new show, without having to get Matt Damon (or Paul Greenglass) involved with the project.
I do agree that Bourne may sound illogical, but I am open to see what they could do, depending if they rely more on physical action than screen-based action for the new show.