So, lately I've had this theory and figured I'd share it here. This is 100% pure speculation and is based on absolutely nothing.
In several gameplay videos, they show a (presumably) early game quest where you meet a potential companion named Preston Garvey, and you can help him and his team of Minutemen fight off some raiders. They've shown that part of the quest will involve the player using a suit of Power Armor to fend off the raiders, then a Deathclaw.
Now, heres an idea of what I think might happen; After you defeat the Deathclaw, a scripted event occurs where the dying Deathclaw makes one last (unavoidable) desperate attack on the player, heavily damaging the Power Armor and rendering it useless.
After the Power Armor is nearly destroyed by the Deathclaw, the player will then collect the pieces of the armor and rebuild it, thus starting the Power Armor crafting tutorial. Since the armor was in shambles and you're putting it back together, this would justify why the starting Power Armor is very weak and would need to be further upgraded throughout the game.
I don't expect that this is how it will go in the game, but if I was a game designer, this would be how I would do it. It would add context for a tutorial and it would prevent early game Power Armor from being too game breaking since it's barely functional.
Thoughts?