So if I'm reading into it correctly, it sounds like the the actual sales are going to be roughly in line with VIII and IX. I don't know how much overlap there is between Dragon Quest's audience and all the competition of that month, but it held up admirably. Especially since the marketing was basically non-existent, and the competition demanded a lot of attention.
I hope Square Enix had realistic expectations though. Dragon Quest seems to be an on-going series of investments. They made the game for PS4, continued to develop it further for the west, made a 3DS version which contains the game in two radically different art styles and perspectives and keep it Japan-exclusive, and for some reason are working on yet another version now too. I wonder if those numbers work out sensibly at the end of the road. I especially wonder how well a Switch version could still do if it'll be so late to the party. I suppose Dragon Quest is a notable enough brand to Square Enix for that not to matter though.
Still think they should bring the 3DS version herr, hopefully its content will at least be in the Switch version...
I'm not sure a 3DS version would make sense in the west in 2018. Especially not after the home console version is already out.