This isn't entirely true. All the quest text, monster says, NPC interactions and more are sent by the server. Sure, the models and sounds are part of the client, but the server tells your client where to place which mobs, how much health they should have, how they react to you, etc.
>The content that is available on Nostralius is literally not available on any live server any more
Yeah, hosting a game server that is no longer available because the company that used to host them stopped offering that option should probably not be against the law. Even single player games are being created as "multiplayer" nowadays, so it's bound to become an even bigger problem in the future.
It's one thing for a company to shut down an older game's multiplayer-only services when the player base dwindles, but with many single player games now requiring a server connection to even function, what happens to those?
At the very least, companies should have a contingency plan for making a "sunset" patch available to allow those games to keep working - even in reduced capacity - once those servers go away.
There is something of a problem here, but the solution (as ever) is not a simple one.
There are allot of WOTLK servers because WOTLK was the most "popular" patch of WoW and allot of work on both the emulation and the database was done for that patch.
However private servers for Cata, MoP, and WoD came out pretty much almost hand in hand with live release, they were and still are utterly garbage but most private servers are.
This is quite big it's the first time for quite a long while that Blizzard went to close an private server, and it's the first time that the server in question was not hosted in the US/CA and was not anywhere close to emulating retail content.
The content that is available on Nostralius is literally not available on any live server any more since Cataclysm which altered all the original "vanilla" content.
This might actually also be interesting to see if this can actually go to court, the server emulation (if done as a clean room) does not infringe on Blizzards actual IP, all the text, sounds, textures models are present on the client side alone the server holds only an itemized database of objects and knows how to communicate with the client.