Justin,
Since the repose of four of our Hierarchs within the past few years (Petros of Astoria, Kalliopios of Pentapolis, Antonios of Attiki, and Matthew of Enoe), the strength of the Holy Synod had diminished severely, and the immediate election of new Hierarchs was imperative. It must be noted that, despite the new elections which were made, there are still vacant dioceses (e.g., Fthiotida, Larissa, Eastern Macedonia & Thrace, The Cyclades, The Dodecanese, Crete, Central & Western Europe) which must be filled as soon as capable and suitable candidates can be found.
It sounds like that is why so many.
I can only guess as why the ages. May the ages were just a matter of consequence?