Comments within tasks, Activity List, Documents, Sub Tasks
Task in Zoho Mail should have same ability as the tasks within Zoho Projects, where persons can comment back on forth. You can see the Activities list, attach docs, and also assign sub tasks etc... We do not need a project based task system but more a year round/day to day, repetitive tasks based systems, where users are using the system as individuals but if a supervisor assigning tasks to users in their group or under their control etc.