First problem is many of the 1/35 figures have horrible faces to begin with. Poorly scuplted with very soft, indistinct details. Newer Tamiya and DML have better details and I've read that some of the newer companies are doing okay, too. Replacing heads with aftermarket offerings from the likes of Hornet will give you a better "canvas" on which to work.
Next, it would help to know what kind of paint you're using.
I've taken to using Andrea/vallejo and have had very good results in 54mm, just slightly larger than 1/35. Check out the figure mags to see what can be done in these scales.