This doesn't have anything to do with Figuarts, but Megahouse is releasing petit chara figures of The Spectre Sisters. It's interesting to me that this is the first bit of merchandize since the beginning of the 20th anniversary to feature a villain, or any character other than the main 11 characters. If the Figuarts continue past Pluto I think there is a very good chance we will see them. Their designs are more striking than Beryl's generals and Crystal is going to be doing the Dark Moon Kingdom arc again so I think they'll be popular enough again.
Koan and Petz are my favorites. I love how they contrast with Mars and Venus. Since they all eventually were healed by Sailor Moon they could be considered good guys. Hulu streaming new episodes of the new English dubs will make a lot of characters more relevant to US audiences I think. It make take a few years but I think it will eventually be like DBZ where the roster just keeps expanding.
Sailor V
Queen Beryl
Queen Nehelennia
Allen/Ein
The Starlights
Super Sailor Chibi Moon
Dark Lady
Mistress 9
Rubeus
Naru
Schoolgirl Usagi
Shrine Maiden Rei
Schoolgirl Ami
Schoolgirl Makoto
Schoolgirl Minako
The Spectre Sisters
Eternal Sailor Moon
Super Sailor Mercury
Super Sailor Mars
Super Sailor Venus
Super Sailor Jupiter
Princess Serenity
Would all be instant buys for me, and this list could have been so much longer.