So what's left for Primaris after this year?

[TheNewman]

...I wouldn't miss Vindicators too much, the Gladiator Valiant providing A LOT of close-quarters oomph (though I'm well aware it's more of a Predator Annhiliator replacement), ...

I've seen that sentiment elsewhere, but I disagree; the Lancer is the Predator Annihilator replacement, that looks like a Heavy Laser Destroyer with the double-shot targeting array. Four shots at range to match the Predator Annihilator at range.

 

The Valiant is the Vindicator replacement; same range, similar average shot count, slightly better average dps to balance slightly worse overall S/Ap.

 

Meanwhile the Reaper might as well be subtitled "we hope you didn't have your heart set on getting the Baal Predator in Vanilla chapters."