Sublime Text uses the system wide antialiasing settings, so the first option is to globally enable cleartype in the control panel (WPF is well known for ignoring the system font settings).
You can force Sublime Text to use subpixel or greyscale antialiasing by appending " :cleartypeantialias" or " :standardantialias" to the end of the font setting. Line spacing can be increased in Sublime Text ("linePaddingTop" and "linePaddingButtom"), but not decreased.
In general, any differences in font rendering should be coming from Sublime Text using GDI to do its font rendering (like 99% of all other Windows apps), and WPF using its own font engine that renders differently.
I'll happily look into fixing any rendering differences between Sublime Text and other GDI based apps, but in general, for any font rendering discrepancies it's WPF that's in the wrong (e.g., google for "WPF blurry font rendering").