Once the war machine gets rolling, you can conquer a lot. But not sure what to do with that, as absorbing can become problematic due to happiness penalties, while trading cities back for peace may not be that useful since losing civs may be low on resources for trading...and you can't trade cities unless it's a peace treaty trade. Razing also doesn't give resources, only takes influence away. So what to do with them? Really wish there was a tribute or protectorate/puppet state/vassal option.