Jandau said:
The one thing bothering me here is Biotics. As far as I recall, Humans in the ME universe can't use Biotics unaided. This is mostly handled with various implants, most of which are fairly invasive. Basically, Biotics aren't something you can "spec out of" as it were. They aren't something you can put down and pick up as the mood strikes you. So will they be providing some sort of lore justification for that or just quietly retcon it? Or just pretend it doesn't exist?
I'm guessing it'll be the last one, which would be sad. One of the things I liked about ME lore is that they tried to provide pseudo-scientific explanations for how the universe works, instead of just being "LOL SPACE MAGIC!!!"...
It isn't like that hasn't happened before in the series. When an imported Shepard is resurrected at the start of ME2, the player can still choose Shepard's class, irrespective of what they were in ME. Thus a Soldier in ME could be an Adept in ME2 and vice versa, despite as you say, the lore precluding it.
The biotics came about relatively recently when we start ME. In fact, the First Contact war was recent too. It's eerie just how recent these monumental events in human history are to the events portrayed in the first game. In fact, Kaiden Alenko as a child was one of the earliest adopters of the implants, a so called "L2", powerful but fewer safeguards meant higher "spikes" but nasty side effects. I believe a Biotic Shepard begins ME as an L3, a fact Kaiden comments on. Presumably L1s were an early model/prototype utilised by the first humans with potential Biotic capabilities, perhaps those already children/young adults. L4s I think were Alliance Ascension only and L5s were Cerberus tech. When Shepard is reborn Biotic in ME2, I don't know exactly what they implant him/her with, but I assume it's L5 since Lazarus was no expense spared, cutting edge tech, etc. (Arguably it could also be L3 since they wanted Shepard to be brought back "the same" as before.) I believe, but cannot say for certain, the Miranda, Jacob and Jack all begin ME2 as L3s, and Jack can upgrade to L5x (L5 retrofit) during the game.
Asari and Protheans we learn are/were naturally biotic as a species. Other species can develop biotics similarly to humans, by in-utero exposure to Eezo, but unlike humans don't need implants. Of the Krogan we meet, Wrex is a biotic while Grunt is not (he is tank bred to be "perfect" genetically). We only meet one biotic Turian (and that in a DLC) and apparently it's looked down on in Turian society. Also IIRC Red Sand the drug can temporarily achieve the same effect as implants in humans (and other species), awakening biotics for a time.