But how significant are the grade 3 buffs instead of the grade 2 ones? While it's been a while since I looked at the actual stat value, from what I recall most the buffs aren't THAT much improved over the GC ones.
No, for a personal house, the expectation is that it's 1 person : 1 house, not 4:1 house. At that point the personal house has basically become an FC house for all intents and purposes without a couple of the perks. I look at the tenant system for the personal house as a nice bonus feature, but not anything that should be calculated in with the math. The cleanest way out of this mess is by introducing a significant number of personal houses until that demand is sated, while also giving the FCs enough wards so things don't degrade further. Given the huge growth the NA playerbase has seen, there definitely needs to be more datacenters in the Americas because otherwise the North American housing issues are going to degrade even further.
Ward allocation (like what SE has stated in the above live letter quote) is something that I see largely as a mitigation for the shell FC problem. Getting more houses into the hands of players does, actually, increase player involvement with the system as more players are going to have meaningful access to the decorating rights than if the entire allocation was given over to the FCs - at least going by the population numbers for https://ffxivcensus.com/ with somewhere between 647,345 to 4,885,698 active characters (their active numbers are likely a gross underestimate), compared to the FC numbers from https://www.xivhousing.com/ which indicates a total of 330,325 FCs worldwide. While the houses are roughly a 2:1 persona/FC split (with 265,668 personal houses to 126,012 FC houses), the house ratio for FCs owned:total is a lot higher than the player owned:total ratio, which is why I'm leaning heavily towards more personal housing as that seems to have the stronger demand between the two.
The big problem I see with all of this is that the number of houses needed to fix this problem is going to mandate (at minimum) another datacenter or two, and then 2-3 more housing neighborhoods. Even then, we still may not have enough houses and we're still going to have the shell FC problem unless SE implements something to solve that problem.
The other problem with the shell FCs... what do you do with them as a fitting (but not excessive) punishment?
Should the shell FC be stripped of their house and have the FC remain?
Should the shell FC be deleted?
What does the mechanism to fix a false flagging look like?
How do you detect a shell FC without (for example) falsely flagging the couple's FC?
There's a lot of questions raised, and not a lot of answers right now, and while the vindicative side on me wants to burn them all to the ground (as I suspect that many members of the Hate Club are shell FC owners), that is not a good policy decision and not something that should be acted upon until an approach of greater finesse can be conceived... which also explains why SE has been so reticent to do anything about the housing issues because of all the possible collateral damage a mistake can create.