How I think this SHOULD have been done
Rather than personal housing, I'd have preferred if they'd implemented variety in the personal rooms:
The personal rooms cost 300k for a regular room with 50 item allowances, and that's it... very basic. Then there is the tier 2 option, pricing could be exponential like they did with the FC housing, but this room is bigger and allows you to have 75 item allowances and a small window garden for personal gardening, having 3 plots for planting so you could potentially get crossbreeds if you so wanted. Then they could do a third tier, same style of pricing, so we're talking in the range of 5mil more than likely for a tier 3 room, but it could have had a second floor, 100 allowances, and maybe a balcony area that would allow you to have a full size garden. Since you can only own one FC room per person, it would solve the problem of people buying out all the plots, and if you didn't have the gil to get a big room at first, you could buy a small and upgrade to a mid/large size room in time.