As an idea, i like it. But thinking about it on paper, it seems frivolous because there for one isn't enough content to get it to 50, would require major rework of current painter/sculptor content from other crafting classes to this one. Seeings as how all housing items are already released for current crafting classes, i can't see them going back and changing that ever.
It would have been cool to have a separate tier of jobs; Disciples of art. The problem with this is that there isn't enough content for two classes, Painter and Sculptor, yet having a single or even two classes as a new disciple isn't worth the work. Which is probably why all housing content got added to current crafters. I believe it was already mentioned, but FF14 won't ever be getting any new crafting classes. Crafting is level progression (new recipes) and once that is exhausted, they will introduce group crafting. However there will never be new crafting classes.
Don't get me wrong, it's not a bad idea; had this been done before housing was introduced and furnishing was allocated to specific classes i would have been all for it. Giddy for a new class. Gardening was released and wasn't even a DoL, stone mason would have been a cool class to add as well but same with painter and sculptor.
Now what would have been really really cool, is if they gave you a blank canvas and built and in game "MS paint", let you create your own paintings/sculptures, preview them on the mb and sell them for all others. That way houses would have unique paintings inside :D