I am applying as a family member of an EU citizen for Ireland. I want to clarify, is it compulsory to write the intended dates of travel on the visa application?
Yes. For a short term visa you need to enter both your proposed dates, for a long term visa you need only enter the proposed arrival, and can leave departure date blank.
I got this information from the actual visa application, and have attached a screenshot below so you can see the data yourself, note how a red * sign indicates a field that must be entered.