If sharding is used, each shard will definitely have more than 75 people. You can log into Stormrage or another popular server right now and you’ll see anywhere from 120-150 people around the AH in Stormwind.
No it’s not, CRZ is when I see players from other realms to make the game seem more full. Hence the name Cross Realm Zones It’s used in old expansion zones and for faction balance in warmode.
Sharding is when there’s a lot of players in one area so the server makes a seperate instance of the same area and splits the players between them so the server doesn’t lag hard or crash.
They are made up of things devs have said to streamer pod casts about server limts and i assume easy math to help make the OPs point that sharding isnt needed.