"... on one of the golden worlds our long-range sensors have identified in Andromeda's Helius cluste

No, but seriously it's time to let it go. Old lore doesn't exist. Read everything as if you never played ME before, otherwise there is only nonsense and retcons.

While it is a very odd line, and caught my ears as ludicrious too, we have to remember the word sensor is an incredibly vague term. We could be talking a hubble equivalent.

Because that would be harder and riskier.  

Five million years isn't a very long time in astronomical terms.

Besides if the lore is a little wonky who cares. As long as its in service of a good story/ good character arcs. I mean don't get me wrong I appreciate good stories, tight writing, and consistant lore as much as the next guy but name one universe that is truly perfect in this regard. I doubt you can. I can't. One of the most classic examples is talking about 'the gates connecting to multiple galaxies' in Stargate the movie and SG-1 and not two episodes later it was revealed that the gate could only connect to the Milky Way. Or heck all those references in Inquisition to the breach still being open even though you closed the damn thing several hours of gameplay ago. I just brush it aside and move on, as long as the rest of the story is good.

Lore, elementary school science, common sense...

I know I am going on on this but what I find a little amusing about this whole long range sensor spiel is why didn't we detect/ see the Reapers in Dark Space if we could pick up planets in another freaking galaxy.

Or they never had any sensors and the whole trip is pretty much a shoot in the dark, theory ride.

Makes more sense that what they wrote.

This doesnt bode good for the codex of MEA.

I just love to see their technical specs for the arks, on how they work.

They could have sent probes out, however I don't think current telescopes can see individual stars let alone exo planets. Perhaps they saw it along the way?

Most likely there was no Reapers between the Milky Way and Andromeda in that section of dark space and that was the only place that the sensors scanned.

The Reapers hibernate in dark space between cycles, but they aren't so numerous that they actually can fully surround the Milky Way. They're just hiding out in a small section of space.

Nope, the AI director is stating this in the recruitment video, which was naturally made before they left.

In fact, I hope that's the gimmick for at least one of our encounters.

In geologic time, let alone astronomical terms, 5 million years is super short. A planet looks pretty much the same... But that's long enough for intelligent life to burst onto the scene.

When we're looking into space, yes, we're technically looking at the past. But some things -- like planets -- probably look about the same.