User blog comment:Ygrain/Leviathan: Do you know what you are doing, Bioware?/@comment-4721065-20120906075655

Why do people think that Synthesis is the only way to stop the Leviathans? Catalyst harvested most of them into the Harbinger when there WASN'T a single other Reaper and they had to hide ever since, even from the early cycles when there couldn't have been more than a dozen of Reapers around. When you choose Control, Shepbringer has THOUSANDS of Reapers at their disposal annd knows very well what they're and where do they live (underwater). They can simply send a couple dozen Reapers to every world with sufficiently deep oceans and purge the Leviathans from the orbit. The worst Leviathans can do in Control is get a few worlds to Eden Prime-like state before the Reapers arrive and destroy them all.

In short, all this DLC has done in regards to ending is a needed counter-point against Destroy, since the deaths of geth and EDI were obviously not enough to prevent it from being the preferred option for the majority of players.