After talking about this in the Guild communities proposal discution, I've decided to make a separate thread for this.

As stated there, many of the guild plots (except the master ones) of most of the guild communities are far too small to be of any use.
With the current auction system, a large guild is tempted to own several master plots in order to build the needed facilities for the guildies, and most of the guild plots remain untouched.

I think that, instead of limiting the number of master plots owned by one guild, the guild plots should be enlarged. Indeed, it would be far more convenient for a guild to own most of their plots in the same location, and with larger plots, let's say 60x60 for the regular guild plots, they'd have far enough room to place the guild facilities, and to place the buildings for the plot owner's convenience. This way, the guild would limit itself the number of master plots owned (or at least would be less tempted to buy many of them), and the guild towns would not be ghost towns with only one large plot built.

Also, another point that hasn't been dicussed, is the 4 lair communities.

Istaria seriously lacks in lair-only guild communities. I strongly advise to add more of those, maybe smaller ones, all around Aradoth. There are many places where they could be added (I want a lair in the Barasavian desert ! ). In addition, to allow guilds to own one of those communities in addition to the two biped ones they have, would ensure a guild to provide the needed lairs to its dragons.