Oh, yeah. I don't think it will happen. And there would be a fairly major initial cost. My thought is that if the numbers are crunched, then the initial cost of the new system, plus the saving I assume it could generate, would then be more cost effective than the present and continued cost of the present system, plus inevitable future Ishgard. Of course, this also has to take into account the life of the game. Though, I would think that an instanced system would be exceptionally better as the game goes start to drift, or if another FF MMO comes out down the line. As players leave the game or log in much less frequently, more and more instanced houses would not have to load. Whereas, if wards start to become sparsely populated, but say 20% of people are still present in a ward... they still have to maintain that whole ward.
I know Yoshi P also wants to redo textures, because they weren't done in high res to start with. At the end of the day it would all come down to money, I would think. Totally random numbers, but if it cost 250k to implement the new system, and that new system, even with some historical wards, then cost 25k a year to maintain, then after 5 years it might have cost them 375k. But, if the present system costs them 100k a year to maintain, over five years that's 500k. So while it would be a 150k increase over the initial housing budget of that first year, it would save them 125k in the long run, and only continue to save them more over time. That is assuming that instanced housing would indeed be cheaper, which I feel like it might be since basically every other MMO does it that way. It's all a numbers game, and I would hope they would be crunching the numbers over a 5 year plan, since we're definitely getting 6.0, have about another year of 5.X, and could possibly see a 7.0.
But no, I don't think they'll change it. I think it's been like this for so long they are just going to bite the bullet and deal with people getting extremely frustrated every time the housing crunch pressure starts to build again.
I would very much like to see the bloody timer go though. If nothing else, do the plottery. The current system is atrocious.