Like i said in another old topic, cities should have one or more important places inside to attract players to come back in it (something like the -future- casinò in Uldah, in which i hope there'll be mini-games as well). Something players need or can enjoy in every city. And not only shops or training places for classes. I noticed for example a sort of music-hall in Gridania that could be 'something fun' in that sense, in the future. So to avoid the concentration of players in one single city only and leave the other cities almost empty (a common problem of all mmorpgs around).

And regard of NPCs in cities, i noticed that cities have almost nothing about city-life. The perfect example is Limsa Lominsa. In the cut-scene introduction we see children playing in the plaza, sailors carrying boxes, etc. That is awesome! But when you actually walk in the city, they are gone.. sadly. In the same way there are few citizens and there aren't their houses to visit (like in ff11). Cities need this kind of 'visual activities' to be real and live. Maybe adding new sidequests they could add new NPCs in this sense. An i agree about the missing houses of citizens (there were in FF11)..