I'm a "Deltoid" here in FAI and according to our computers the ATL-EZE route will be operated by an MD-11. All Brazil flights (daily ATL-GRU and thrice weekly ATL-GIG) will go back to 767-300s, though it seems to me the traffic on these flights warrant something bigger. It wouldn't suprise me to see 777s flying down there sometime soon. DL hauls a hell of a lot of cargo between ATL and Brazil (and most of the rest of S. America too; nonrevs have routinely been bumped out of SCL because they're stuffing those birds so full of cargo they can't afford the extra weight!)
Another route that is losing MD-11 service this summer is ATL-SNN-DUB, which will be upgraded to 777 (I believe the first 777 service to Ireland by any carrier). Last I checked ATL-AMS was still to be served by MD-11 but ATL-BRU will go back to 767-300. Also with the new LAX-NGO and JFK-NRT service in April there will no longer be MD-11s flying CVG-PDX-NGO and ATL-PDX-NRT. Losing the domestic legs, this would seem to free up some MD-11 time for the new international flights.
As for DL's upcoming foray into the Middle East, given the tenuous state of affairs in Israel (and thus the region as a whole), it seems like DL picked a really lousy time to start brand new services to TLV, CAI, and DXB.
One service which had been announced but is still not in the schedule is ATL-FRA-DEL (using 767-300). Dunno what is holding that one up.