EK are not going to give you the name of individuals working for them on a flight, both from a confidentiality and a security perspective - for all they know you could be a crazy person trying to stalk a crew member (it does happen), and for them, only one instance would not be worth it for their staff retention - crew are a gossipy lot. Imagine if word got around that someone in customer affairs gave the name of a crew member to someone who wrote in and just asked for it and that crew member is now suddenly being harassed via Facebook or what have you. Not good at all for the company. You may argue that they already display their names (and full names for senior staff) on their badges already - but this would only be another potential headache.

However, if you send in the details of your flight (booking reference/ticket number) and where you were sitting, that will be enough for EK to find out who exactly was serving that cabin at the time and the purser in charge/line manager of the crew in question will (sometimes) get comments forwarded on to them.