Is there something wrong with thinking this way? You act like "it's just gameplay" should mean it isn't even worth thinking about. And I didn't mean biotics is based on strength, I meant it's based on training and skill and not knowledge of anything mechanical. Biotics train by further fine tuning their control of their nervous system, so the increased power upon level up actually was because of Shepard's training and not knowledge building. Like most of what fitness raises, biotics are separate from equipment knowledge.
I don't necessarily mean that gameplay isn't worth thinking about its just... there is distinction in Mass Effect, a line between what is true in narrative lore and what happens in gameplay. There is in just about every game, really. Why is it that a single headshot from ANY gun doesn't kill an unarmored, unshielded enemy? Because its a crappy weak gun you get in the start of the game. This is ESPECIALLY true in Mass Effect (the first one) since the starting weapons all rather suck. Infact that game doesn't even have a headshot system so it doesn't matter where you hit them. Does that mean headshots don't do more damage during the time before the geth invasion is it just a gameplay thing that isn't meant to so heavily picked apart for meaning? I don't know. I side with it just being gameplay.
Shepard, a non biotic, can learn biotic skills as bonus powers. Does this mean that he's secretly a biotic with a biotic implant in his brain and amp in his neck? No, it just means its a gameplay mechanic. Shepard's skills, points, armor and weapons carry over in new game+. Reasons? Gameplay mechanic. There are powers and talents that you only get if you have a certain team mates loyalty. From a narrative perspective you could say well maybe this is because they taught it to him after becoming close friends. These powers also carry over in New Game+ though so that argument doesn't hold water. It's just a gameplay mechanic.
In the first game Shepard, a trained N7 (best of the best) and SPECTRE cannot shoot accurately to save his life - not until leveling up skills tied to that certain weapon. It's as if Shepard starts the game as a novice or rookie even though he is an N7 and Spectre. Why? Because its a gameplay mechanic, its a level up system, many games have them. Shepard can use Dominate on reaper troops. Is it because he's secretly Leviathan? No, it's just a gameplay power.
You can carry hundreds of weapons and armors on your back in the first game. You can turn practically anything into omnigel and use that gel to fix or crack or hack anything. You can revive geth with medi-gel. A krogan can be killed instantly by a sword in the gut. Your squadmates can be all be brought back from death after having a banshee impale her entire hand through their torsos.
In the first game tech powers were fired as small discs like grenades yet in the other games its either instant or a dramatic effect of flying ice or fire. Shield Drain magically vampire leeches the shields from your enemies and gives it to you. Reave magically leeches health from enemies. The collectors are awakened and fighting the reapers. You can make out where cloaked enemies are yet when you cloak you're instantly forgotten about by the enemy. You fight plenty of biotics but none of them seem interested in suspending you in the air and riddling you with bullets. Jack can biotically punch and destroy two giant mechs and blow a hole in the hull of a ship but is considerably nerf in gameplay.
Hell biotics themselves seem to be pretty far off the bat when it comes to being true to the narrative as a far as gameplay is concerned. Biotics in the narrative are told to be a tiring effort yet I can run around throwing them around constantly, not even using a gun and never get tired. If they were as tiring as some of the novels suggest Shepard should had passed out by now. No amount of being tough and strong is going to save you there, imo. Though it has been years since I read the novel so I could be remembering it wrong. Also in the first game biotics, if I recall correctly, worked on even shielded enemies but now you have to take down the shields first.
But I digress. I wasn't saying you're wrong or anything of the sort. I'm just saying that sometimes it is possible to over-analyze things. When it comes to gameplay, especially in a RPG with stats and levels and multiple tier weapons and difficulty settings... you have to be a bit more lax, imo. Personally I feel there are too many instances in Mass Effect where the gameplay isn't persistent with the narrative for me to really put much stock value in it as far as having the gameplay reflect lore. I don't judge it for it though, since I honestly don't expect it to follow lore to the letter. Afterall, it is just gameplay. I don't feel you're meant to over-think these things because if you do you end up with all the issues I described above. Though that's just me.