It would add a dash of polish that other text editors on Windows don't possess. You seem to have have an appreciation for the aesthetic quality of your software (good job too!) and I think DirectWrite would make it sing. Certainly, in Firefox 4 and IE9, text looks much better to my eye, particularly the spacing/kerning and y-axis anti-aliasing. Plus, because of the sub-pixel positioning and improved anti-aliasing, it makes fonts that previously look terrible under GDI look pretty good. I threw together a gallery of screenshots for the Google guys to show how their new fonts browser is let down by Chrome. Here: http://min.us/mvoZaZS
(view originals to actually see the differences).
But perhaps people prefer the more crisp GDI rendering, for coding at least?