I haven't played Minecraft in well over a year but from what I can remember, they brought out some battle mode thingy which can have up to 8 players per battle.On another note 1.12 is on its way and looks good for builders wool is more vibrant and there are 2 new block types which all use the color pallet that the wool does.
However I remember it was awful as it was so damn laggy that it was basically unplayable. If you have played on a friends map with a maximum of 3 players, it lags extremely badly, mobs can hit you from like 10 blocks away and if you were to mine stuff, the drops wouldn't show up half the time.
So try taking 8 players and have them fight each other is so incredibly laggy.
Also as said in a tweet from dinnerbone they only have 4 more block ID's left but they have been working on a solution.
First of all, Let me point out that MC is having the exact same issue that TM has ATM. I find it funny that TM was beating MC in terms of blocks there for a while.
I feel like MC could work around the problem by converging a lot of its blocks into one ID.
If they did what Craig did with detail blocks and made them texturable, They could consolidate all of the stairs into one block, And make some of the half blocks into the other ID.http://minecraft.gamepedia.com/Data_values/Block_IDs
Look at all of the space they could free up by doing this. All of the fences, All of the stairs, All of that could be fixed. Their block data structure could also probably allow for more than 16 textures because it seems like they can use strings for block states.