I think this is smart, though I think it’s a little unrealistic. They’ve got a Joker film, a Harley/BOP film, a Suicide Squad film and a New Gods film in the pipeline at various stages. There’s no way they’re going to stick to one new series a year. Right now their strategy seems to be prioritizing low budget films and hoping they overperform. That gives them more room to manage risk, especially if the films remain somewhat disconnected.
It does mean that properties like Superman are probably high risk for WB, because he’s proven to be difficult for WB to get right and he kinda requires a high budget (though perhaps Aquaman indicates that doesn’t have to be the case.) Properties like Green Lantern Corps, and I assume New Gods, would similarly be high risk given GL’s last film and the New Gods concept. In that case, yes, it’d probably be smart to spread out these higher budget films, and to take their time with them.
With Superman, they should probably also weigh the question of whether or not it’s worth it to stick with the current version or reboot, though my sense is that they are waiting on a director to sign on and make that decision for them, similarly to Reeves with his Batman.