It's a shame really, as I feel like the Arkham series of figures are quite possibly what strengthened DCD/DCC's popularity and reputation when they first started out with them. The line grew so fast in popularity, and figures sold out fast too. I'm pretty sure it was their best ever selling line at the time.
It's sad that momentum on the line has now slowed down so much that it's leading to figures being cancelled. I think this line deserved to be kept on top of instead of having huge gaps in-between new waves of figures, and that way it would have kept it's momentum. They should have had way more Arkham Knight villain figures released/announced by now and in good solid waves of them too, not the random assortment we got with Ivy in. They should have announced an Arkham Knight Batmobile too (as much as it was hated by a lot of fans I bet collectors would have still snapped it up and it would have boosted interest in the line too). I feel like pre-sales would have been higher for these figures if the momentum in the line hadn't slowed so much....
It seems the future of Arkham figures is a little shaky at the minute, and I guess DCC's comments of 'we'll return to previous games for future figures' can now be assumed won't happen. I don't see them doing figures from the new Arkham VR game really, so unless a proper new Arkham related game gets released soon I don't see them making any more than what's due to be released. Especially if the pre-sales aren't supporting them.
On the other hand, they may know something we don't, and there could be a new Arkham game just around the corner which they're currently working on and are unable to say anything about. There's a chance they could be making figures for that I suppose and putting these Knight ones on the back-burner until then.