I'm no modder, and definately not a game developer, but could it work? I mean you can already pass thru a dead pile of mirelurk queen..I really don't have issues with companions in doorways, but I have had a few times where I tried backing away from a mine or a turret, and there's my trusty K-9 right behind me while my legs get blown off..

You can command them to move, so their being in the way isn't a big problem in Fallout 4.

No worries. Mods will make no-collision with companions as soon as possible.

Yea but while a mine is ticking away, and your companion blocking you from backing away..no time to command him to move