MEA is planning to replace its A321s that it has had in its fleet since 2003 with brand new leased A320s.
MEA sold two of its six A321s last December to Turkish charter Atlasjet. These were replaced by 2 new A320s delivered this year. They will sell another two A321s this year to be replaced by two more new leased A320s leaving only two A321s which I presume will be sold next year.
Interestingly, the latest A320 and the remaining two to be delivered this year are all leased and are powered by CFM56 turbofans instead of IAE V2500s like on the rest of MEA's owned A320/A321 fleet.
The decision to lease rather than buy the latest batch is due to upcoming new offerings by Airbus and Boeing, the A320neo and 737 MAX. The leases are only for six to eight years after which they will be replaced by either the A320neo or the 737 MAX of which MEA is currently evaluating both.
I don't really trust Wikipedia, but the MEA page mentions that they are considering adding another A330. I haven't been able to find any evidence to back this statement:
MEA will join SkyTeam next week.