That may be true but summer memories took over a year(1 year and 1 month?) to release so even if they DO give winter memories special attention i dont think we can expect something below the 6 month mark(since they have so many projects)
I'm just assuming here but, I think the reason the last game took so long was the issues they had encountered with implementing the text. Either that or there was only one Translator taking their time attempting to convert the subtilties of Japanese tone into English. (which can also take a lot)
I think the former, because judging from what Kin-Kun had been doing in making the unofficial patch. There were many bugs that Kin-Kun had to extensively work on just to put in small features, placing unused art, and fixing dialogue.
Plus the Dev said that there would be problems with RPGmaker if added any more content like DLC since its already a little over the RPG size limit. ( I can't quite remember the exact issue but it was along those lines, it's on his "Ci-en" I think)
It all points to how modified this game's RPGmaker is too. I can guess that certain english sentences would be longer than original and mess up the storage limit on text. Which would agitate the program the game's running on, and translating the HUD probably leads to a crazy amount of bugs.
I'm no Dev, so this is just a gamer's hypothesis from installing mods.