@Sezme, thank you for your detailed reply! As an English teacher and a Japanese student I think these are interesting issues.
I can see what you mean about the pace. The Japanese course where we used Marugoto was an intensive 4-hour-a-day-every-day course (!) so the pacing worked out well for us. But I definitely agree with you about the lack of references/indexing that would make it easier to find grammar points later. That was probably my biggest complaint.
Anyway, apologies everyone for derailing this thread! I just got excited when I saw someone mention Marugoto because it doesn’t come up very often.