The mob area

So I've taken it upon myself to improve this place for your enjoyment. But I could really use some ideas for buildings, etc. Have some for me? Post 'em here!

 

I don't even use the arena. I'll have to check it out sometime before I give suggestions. But in general, it seems everyone is enjoying it

 

How about for the mob arena the tower could be for a weekly/daily raid where a group of people go to fight rare mobs and sometimes we could have a potion master who would be paid cobble or something to use splash potions on this raid party it would be fun!