One of the plugins is for anti griefing, called Citadel.  Let's you "reinforce" blocks and objects(doors and chests reinforced this way will be locked).  Makes it harder to do that sort of thing.  What it does is basically makes the objects take more breaks to actually break.  You can use stone, iron or diamond.  Stone is 32 breaks, iron is like a hundred and something, and diamond is like three hundred and something.  I think it's a really solid plugin, and it makes stone valuable, and increases the value of iron and diamond, so it beefs up the economy as well as preventing grief.  

The game functions a lot like nation role plays, though not everyone(some do) actually "role play" their characters.  

Griefing is pretty rare, mostly thanks to Citadel, and players who join for no other reason than to cause trouble usually get discouraged quickly and leave.  The mods aren't "weak" so much as they choose not to interfere.  The [i]community[/i] is pretty strong, though.  There are a lot of groups, and a handful of them are incredibly strong.  They don't always get along, and there have been battles raids and war.  

A note about nations:  There's a lot that have been there for a long time, and those that are still around are pretty big and wealthy, and will gladly take new players in(usually on a probationary period).  I don't advise trying to start your own nation, unless a lot of people from the Guild get in on one together(in which case I'd honestly probably jump ship from where I am and join).  Lots of new players try to start nations and they almost always end up being one person groups that just get absorbed by the larger ones.  

If it helps entice anyone, they're working on putting in a plugin that adds ships, airships, and submarines.  It doesn't work very well at the moment, but they're revising it.  There's no guarantee it will be added, but it's a possibility and you can play with the plugin in their test server.