When you first see the human reaper you can ask EDI about it as she is patched into the collector network and one of the things she mentions is that the reapers were unable to make a prothean reaper which is why they even bothered to make the collectors. Best guess is that all their trading for genetic samples was to determine who would make the best reaper from the new species or even which were actually capable of being used to make reapers. Evidently humans were settled on as the best or only solution. Puts that virus they released on Omega in a new light too, an easy way to get rid of the useless species while leaving the humans for collection.
I don't really get the objection that ME2 felt like you didn't do anything. At the start the collectors were taking tens of thousands of human colonists and you had no idea why. By the end you've stopped them and killed a reaper in progress. Sure, the main reaper fleet is still out there and still coming but you stopped this plan at least.
I'm just curious whether Harbinger is currently inside the galaxy much like Sovereign was or if he was controlling the collectors from dark space.
I don't really get the objection that ME2 felt like you didn't do anything. At the start the collectors were taking tens of thousands of human colonists and you had no idea why. By the end you've stopped them and killed a reaper in progress. Sure, the main reaper fleet is still out there and still coming but you stopped this plan at least.
I'm just curious whether Harbinger is currently inside the galaxy much like Sovereign was or if he was controlling the collectors from dark space.