So, did you sign up? What happens upon that?
As for the contemporary arena shooter landscape, here's a brief overview:
1) Toxikk. Released last year to no fanfare. UT-style. Has a "free edition", which is pretty nice of them. Windows-only, ports not going to happen. Steam-only, but doesn't seem to really depend on it in any way (?).
2) Reflex. Just announced the release date to be this March. Today, actually. Probably won't see any fanfare either. Quake-style. Windows only, but they did sort of say they kinda want to do ports (read: they'll do it if it goes really well for them and isn't too much trouble...so probably not). Steam-only, and likely to stay that way, since they've tied their level editor (which is an in-game thing ala Doom 2016) to the Workshop. The rest of the features don't seem to depend on Steam (?).
3) Unreal Tournament. The new one. Will probably see some hype when it's near release, provided it ever gets there, as Epic doesn't seem to be in a hurry. Free (with source available), cross-platform, doesn't seem like it'll require Steam...oh, and it's still what you'd want from UT, and not a class-based shooter. It couldn't get any better for a MP shooter...except it's UT-style and not Quake-style :p
4) Diabotical. Previously known as Reborn, it was, uhm, reborn as Diabotical on KickStarter. Except for that, not much else is known: no release date and no clear indication of style. KS page says "Windows and Steam", which...eh...FFS.
Quake Champions isn't on the list, as you can see, since it's a class-based shooter. I mean, sure, it was a Quake mod that invented the class-based shooter, but Bethesda isn't going for dat Team Fortress feel, they're going for dat Overwatch money.
How will that play out, considering they're late to the party...I mean, as a Quake fan, I'm curious about it, but have reservations. Class-based shooter fans...well, in fact, ALL online shooters since the last UT have been either squad-based or class-based, and at some point the squad-based (typically military) shooters basically turned into class-based ones - that's what happens when you add a loadout and XP system to a squad-based shooter - the phrase spoiled for choice comes to mind.
The appeal with Overwatch is the character-as-class, MOBA-style thing, but even then, there's Battleborn, Overwatch, Paladins, and probably more games incoming (Lawbreakers is one, Bleszinski's new game post his departure from Epic)...and that's not couting the TPP MOBA-style games, like Smite Gigantic, Paragon (Epic again), and Bethesda's own halted entry, Battlecry.
I suppose we'll just have to wait and see. In the meantime, I'm not rebuying Q3A for $20 (FU Bethesda), but I can be shot at random European OpenArena servers. Hint, hint.