Morbad, as I said not really game for a realism discussion so I'll accept that you understand how magic shields in the future would actually work and leave it at that.
My initial point was indeed that the developers have their vision and I've always understood it that missiles were never intended to be highly effective against shields. The only factor that matters is game play, shields aren't real. They're 100% in the game for game play. And they're intended to provide excellent protection against anything but lasers.
It might be your perception that this change is purely driven by the call for PvP nerf; that's understandable. But the bigger picture was adequately explained by Mike. And the proposal for change was congruent with that bigger picture. And, most importantly, the only people who will "lose out" from the proposed change are players who relied on missile damage against shields.
By your own admission, missiles are too expensive against NPCs for this usage. So the only losers here are PvP players. Who, apparently, can't hit with dumb-fires unless fighting big ships or static, low skilled players.
So, that further reduces the pool of "affected" players down to PvP players who rely on missiles to obliterate big ship shields in PvP.
We're talking about a tiny fraction of the player base potentially being disgruntled because of a change that many probably agree with; most crucially, a change that is in line with FD's vision - not a newly emergent vision, either.
Large positive gain, low percentage loss, in line with consistent design vision, minimal impact to game, design retains full functionality as intended.
The very definition of a good design change. Your argument essentially boils down to an assertion that the change isn't needed because it's a fringe benefit. But that's exactly the reason it's a good change.