Is there a specific point size range (e.g. anything above 30-40pt.), generally speaking, in which TrueType hinting is unnecessary for excellent rendering on screens that typically require TT hinting?
I vaguely recall reading something on Typekit about how TT hinting at large sizes on-screen can actually produce jagged outlines/rendering, and Postscript hinting is preferred as the outlines render much smoother.
I've seen plenty of typefaces that have a 'suggested use' at either Medium or Large sizes, and am curious if at larger sizes TT hinting is still critical to its optimal rendering on said screens.
You read, I guess, about how Typekit changes to CFF font files and rendering on Windows for CFF that avoid CT rendering at large sizes because PS rendering looks better there.
Windows GDI ClearType anti-aliases TrueType fonts in the horizontal direction, but not vertically. At small sizes with most fonts, the lack of vertical anti-aliasing is slightly irksome, but still produces better rendering than what Windows GDI does for OpenType CFF.
At larger sizes, that same rendering of TrueType is just irritating, and OT CFF just looks better.
What TypeKit does, for some fonts which they expect will never be used at small sizes anyway, is just to serve them only in OT CFF.
Note that with DirectWrite, Windows renders both TrueType and OpenType CFF with ClearType, with anti-aliasing in both directions. So everything looks pretty good.
It becomes less the case when 'everything' includes all type designs over 30 pt. and reserves special cruelly for the poor shallow curves of type. So, sadly, the design must decide what available technologies are best for it at what sizes, but because there isn't any software listening, only the experienced designer can tell by looking.
DirectWrite AND Windows? Not sure what you think I said. But I definitely think GDI ClearType rendering has issues, and especially so at large sizes—or as you say, with shallow curves (nearly horizontal ones, in particular).