When the complex/richtext text was introduced the code doubled, the old path was keep around for safety and entire new implementation was added.
Not that last users of old path were updated to use the new implementation we are able to remove the old code.

There are list of methods and classes that are not complex-aware can be removed:
PGText
NGText
PGTextHelper
NGTextHelper
Toolkit#createPGText
StubToolkit#createPGText
DummyToolkit#createPGText
QuantumToolkit#createPGText
Graphics#(String, FontStrike, float, float);
Graphics#(String, FontStrike, float, float, Color, int, int);
TestGraphics#(String, FontStrike, float, float);
TestGraphics#(String, FontStrike, float, float, Color, int, int);
BaseShaderGraphics#(String, FontStrike, float, float);
BaseShaderGraphics#(String, FontStrike, float, float, Color, int, int);
SWGraphics#(String, FontStrike, float, float);
SWGraphics#(String, FontStrike, float, float, Color, int, int);
J2DGraphics#(String, FontStrike, float, float);
J2DGraphics#(String, FontStrike, float, float, Color, int, int);
FontStrike#getStringWidth ***see note****
FontStrike#getStringHeight
FontStrike#getStringBounds
FontStrike#getStringVisualBounds
FontStrike#getOutline(String, BaseTransform);
FontStrike#getOutline(String, BaseTransform, Path2D);
T2KFontStrike#getStringWidth
T2KFontStrike#getStringHeight
T2KFontStrike#getStringBounds
T2KFontStrike#getStringVisualBounds
T2KFontStrike#getOutline(String, BaseTransform);
T2KFontStrike#getOutline(String, BaseTransform, Path2D);
CompositeStrike#getStringWidth
CompositeStrike#getStringHeight
CompositeStrike#getStringBounds
CompositeStrike#getStringVisualBounds
CompositeStrike#getOutline(String, BaseTransform);
CompositeStrike#getOutline(String, BaseTransform, Path2D);

The one method is the list above that is in use is strike#getStringWidth():

TextAreaSkin and TextFieldSkin use FontMetrics#computeStringWidth("W");
Toolkit.getToolkit().getFontLoader().getFontMetrics(font.get());
FontMetrics calls in FontLoader:
Toolkit.getToolkit().getFontLoader().computeStringWidth(string, getFont());
FontLoader calls in PrismFontUtils
PrismFontUtils.computeStringWidth(prismFont, string);
PrismFontUtils calls in FontStrike
strike.getStringWidth(string);
which naively accumulates the advances using getCharAdvance


That can be workaround a number of different ways:
A) re implement PrismFontUtils.computeStringWidth to use FontStrike#getCharAdvance
B) replace FontMetrics#computeStringWidth(String) by FontMetrics#getCharAdvance(int);
C) change TextAreaSkin and TextFieldSkin to use a Text node instead of internals is currently uses


I like (B), but (A) is the least intrusive.