Long story short, none. Aigis, FKG and Kamihime have been DMM's most successful R18 games for a good while, with no long-term competition in sight, and Nutaku essentially ruined two out of three (Kamihime, I suspect, only survives because the original DMM team keeps a tight rein over Nutaku). They can't switch to a new top-tier game to generate interest, because they ran out of these.

There is still some potential: Games like Otogi Frontier, Sora no Kanata no Dystopia, Idol Wars and Taimanin Asagi Battle Arena are consistent R18 rankers as well, recent and upcoming titles like Jewel Princess, Unitia and Girls' Symphony: Encore may make a lasting impact, and there are also high-ranking worksafe games like Kanpani Girls (another Nutaku victim), Shiro Project, Touken Ranbu and of course the elephant in the room (Kancolle). But with the lack of major DMM localization announcements during the past few months, it seems to me that even DMM teams are aware of Nutaku's incompetence and wary of handing their games over.

DMM also recently started adding foreign language support to their games, so the best course of action is probably to let Nutaku die so that DMM can take over as a platform. The Taiwanese version of FKG, for example, recently moved to DMM after its foreign developers announced service closure, and it seems to be pretty well-managed now.

If you guys actually go ahead and kill off Nutaku's FKG, there's a good chance that it'll move to DMM, and you'll get to experience the trademark FKG dev generosity in English (if you think that EN FKG is in any way good, consider that DMM players get something like 400 flower gems in a good month, with ~1500 stones available to free players during the last six months).