First, It's important to get a single dashboard view of all your activities in the calendar format. The only missing thing is getting 'TASKS' listed in the calendar view.
Second, a task must have a start, end times and a reminder option.
Third, a task might include making calls, attending events etc. and also may include the involvement of more than one contact. The option to link it to multiple modules is a must.
I hope Zoho is working on these.