a more recent interview:

Nova Crystallis: Is add-on support is still in the cards and when we might be able to expect it if it is?

Yoshida: In terms of add-on support the design is in progress – we do have programmers assigned to that task with coding just about to begin. When it does finally come to fruition we will be able to provide it along with a manual for it. We do have to be honest – production is a little bit behind only because the development for the PS4 version has been going very smoothly so we’ve been trying to put more effort into that as well as a large milestone we want to hit moving forward is to start service in China so we’d like to make for a successful release in that region as well. We are hoping that the support will be offered maybe after same timing.

We have made a lot of updates to the user interface so looking at it we’re starting to think “Do we really need add-ons?” It’s getting to that level where it’s so much improved. But I’m sure people want to do other things such as changing the skin and things like that.
sources: here