What I think is really going on:
Spinefarm attempted and partly succeeded in manipulating COB's musical direction.
Alexi has stated all the time he's not going back to the neo-classical stuff and says they were inexperienced in the old days. However, the past year has shown signs of the band starting to enjoy their older, more passionate-sounding music again, and now they've embraced the good aspects of the old style to their new album.
Bodom changed labels because they wanted the label not to interfere with their music in an unpleasant way.
There is now a plan to cultivate the desired aspects of the old-school Bodom material into their current musical taste. This way they can keep their beloved heaviness in the music, while incorporating more wild musical try-out in the mix, and returning to the darker and more atmospheric sound world. This gives them freedom to use the marketing strategy of "returning to the roots" and all that, but only to the extent when they don't have to discard elements they like from the music.
So practically I think whatever's going on it serves everybody...
And I have to admit: I'd rather have an old-schoolish Bodom album dictated by the label, than to have another RRF written spontaneously by Alexi.
My gut feeling is Nuclear Blast was in contact with the band saying "you know, we could support you returning to the more interesting music and artwork", which the band thought was what they needed.
Or we could be less confusing and just say Alexi feels like doing more darker and less dull music again.
The "defined plan to return to the roots" is a marketing strategy. Alexi doesn't want to start doing neo-classical again and he doesn't want to get inexperienced again, he just wants to obtain the best elements of the old Bodom albums to the new material, the plan isn't to write SW pt2, HB pt2 or FTR pt2, the plan is to write a sequel to those, I suppose.
To sum it up, I understand this will be when they grasp the point again, since they forgot what they were all about with HCDR. Each of the old albums are very different, but they share the deeply interesting soundworld and energetic composions as similarity, plus the epic artwork theme - which are to return with this record...
What I find interesting is, RRF was described to have more melodies than Blooddrunk (on a quick count RRF contains 11 distinct melodies, compared to Blooddrunk's 8 based on my view on melodies), yet Blooddrunk sounds more like the old albums as it's darker. This new album is described very dark and more melodic than RRF - so it seems promising on paper.