I would like a global chat too. It's pretty fun sometimes even though it's easily spammed. A message system would be great! And a ''friend system'' where you could add and see if your friends are online. Maybe even a way to chat and talk to them through another chat tab maybe?
I have been playing other similar games for a few years and I never use the global chat. I am not sure it is needed. It is mostly just spam and I'd rather the devs focus on gameplay.
Global chat is always a bonus for recruiting but I understand that it is very difficult to moderate. The swearing is only a tiny portion of the moderating that would be needed!! Anyone that has played Clash will no doubt have seen on Global "I'm 12 want to be my girlfriend" and other such freaky messages!! The only way that global chat would work is if it was monitored properly and anyone saying anything inappropriate be kicked straight away. I like the idea of the admins recruiting a team of moderators and would be happy to help out with this (just line my pocket with a few gems!!) and I am sure that they would have no problems recruiting mature gamers to help out! But the main thing to consider is what purpose does a global chat actually have other than recruitment! I can't really think of anything much.
Don't forget player to player mail. Say I want to discuss something with individuals but I don't want to give out my real email address, a player mail system would be great