I was very surprised to read your post about the Athens Ledra. I stayed there for a week in July and it was one of my best ever stays at a Marriott -- including front desk, a wonderful concierge, and the fantastic executive lounge. What problems in particular did you experience? If you feel they had to do with particular individuals at the desk, I would suggest contacting the hotel manager.
It sounds like we had totally different experiences, so I'm wondering what if anything has changed in five months.
I was in Athens May 22-28. I used pts. for one night and paid for the rest ( believe it was $300 US a night). I had made my reservations through Marriott and was going to use a buy 2 get on free and then also use the one night of points. The room I booked since I was paying had breakfast in the restaurant include along with tickets to the Acropolis. First, since my sister made the reservation (she's platinum, I'm platinum) they would not give me priviledges to lounge since I had booked a breakfast they finally relented after a big hassle. Then when we went to eat a restaurant they said we no longer could do that we had to eat in the lounge( but we would get to continue paying for it anyway). Next, they said we would not be eliglble to use the free night (even though it had been approved by Marriott), they would not even call reservations they just said they would not honor it. I also got stuck paying for an extra person in my room (20 a night) eventhough they were in my sisters room not mine. Concierge made reservations for a tour and then failed to tell us what we needed to do or go to be able to do it. When we asked them what we were supposed to do they just laughed and said it was already gone. I did talk to the manager once he arrived on Monday morning and asked what he could do but I was so disgusted by the 3 days I had already spent there I told him there wasn't much, so he watched as got my bags and checked out. I went to the Intercontinental down the street ( paid half the price) had breakfast in the dining room (wonderful) and enjoyed the rest of my stay. By the way after I checked out my sister got moved to the presidential suite.