@Nekrage
This as well.
While city sieges may happen due to strategic spots, it's highly unlikely at this point for it to happen due to 'running out of space', as a matter of fact we're having the opposite problem right now as there are still low number of players.
In the future however, city sieges are most likely to happen out of...
- Strategic spots.
- Competing guilds.
- For the sake of conquering - Which wouldn't work so well in Syndesia, Tartaros maybe.
As of this moment though, there is absolutely no point for people to purchase a governor pack (or beyond) if they're not running a guild or a community. Sure it helps the developers with funding, but for you on the receiving end, it's not necessary. This is also what @Prometheus has mentioned several times, even if you email them about purchasing an Aristocrat pack - "Keep in mind that you don't need a governor pack to start your own city."
I was keen on buying one myself until I realised that this pack isn't necessary for a relatively solo-player like myself, i'm much better off joining a guild instead.
There are plenty of land slots available for players outside of cities that can even stand as their own semi-formal community, however they still need the benefit of a city as it can provide NPCs and other services that are only available in such said settlements.
So, with that being said for you who bought a governor pack, you still have the access to all of the governor perks, you can still establish your own city/settlement at launch but you would have to wait until more players join your city to make proper progress in it.
While that is happening though, other cities will/can experience the game much better than you would so it would be much preferable for you to join one instead and perhaps one day build your own city, i'm certain that there would be lots more 'stragglers' who just joined the game at that point in time.
I would also strongly suggest to watch the Q&As available on the website, some of them are probably outdated as some things had to change overtime but it will still give you a good foundational basis of understanding with the mechanics of the game.
So in other words, and for those who will run into this discussion:
Governor/Aristocrat pack would only benefit you as a person if you have a guild/community ready to go, if not then it won't really be much of a use for you.
and given with what @Prometheus has said about the size of large cities, it looks like the entire population could easily fit in one city right now, and most cities being built aren't even enough for a small city.