The ability to alter the size of the NPC text box was arbitrarily removed in today's 4.1 patch.
As far as I know there was never a way to save the text box scaling option, so you had to alter it every time you logged in.
That was still enough to get by, and I greatly appreciated the option.
For those of us with impaired vision, it allowed us to read important dialogue comfortably.
I see no reason for its removal, and it wasn't brought up in the patch notes at all.
Lowering my resolution isn't a reasonable workaround to the problem, because I've still got to fit the other 20 or so HUD elements into my screen space.

Being able to enjoy the story through NPC conversations and cutscenes is an integral part of the experience, and I'd really like to do so without straining my eyes.

I have no idea how to get the issue noticed by the right people, but I really hope that this isn't buried and forgotten.