There was no private housing in the beginning - only FC housing. It is normal to give FCs a chance to grab a plot first before letting personals take over. Normally the waiting time for private housing is 2 - 4 weeks after FC housing was released so it should hit soon.
As Spriggan/Twintania is still new and attracted a lot of new players who created new FCs some still struggle to get enough fonds to buy even a small plot. We, who moved there with our years of experience and our bags of gil, have a hard time understanding the struggle of fresh players and fresh FCs. Personal I think it is fair to give them two or three weeks time to settle in.
I can only talk for Spriggan but last time we checked there still lots of larges, meds and hundreds of smalls left. So even if this will be postponed another two weeks people should still be able to grab good plots (even good large plots) for their personals.