Well, I heard, this would cost more energie, than the universe itself has got.
So it's plausible, but impossible.
I'm not quite sure, if I understand what you mean.
The max pitch is now about 60 degrees.
But even without moving at this pitch, right now you can attack ships that are directly above or below you - if you use 180 degrees or 250 degrees weapons, you can even fly with 0 degree pitch under or over them.
So I guess, there is a mechanic, that resolves the "problem" of attacks coming not from the side right now, so that shouldn't be the problem for increasing the pitch to 89 degrees.
Hmm. It looks like only 45° to me when I max it out and look from the side. I could be wrong, though.
And yes, you can attack a ship directly "above" or "below" you with wide-arc weapons, even with 0° pitch angle, but that's not the "problem" people are complaining about. It's specifically those narrow-angle weapons that they're talking about.