I noticed this right away when testing sodipodi and it
was kind of a "show-stopper" for me. The outlines
(strokes) of objects are displayed 2 pixels wide if
very thin. Depending on the thickness, the color is
faded. I think this is very odd behavior and not very
useful in the first place.
I often used Corel Draw to prototype designs for later
editing in bitmap-based editors. This means the view in
the vector-based drawing application should resemble a
bitmap as close as possible.
It should at least be possible to fiddle around with
thickness settings so that it is possible to achieve
any thickness at full color on screen. At the very
least it should be possible to have "hair lines" lines
(= 1 pixel on screen) with some setting. I know this
might be a problem because SVG apparently doesn't
understand "hair lines" (or didn't when I last
checked). Still, it is possible to achieve this effect
with very thin stroke-width settings in most SVG viewers.
I apologize in case I overlooked an option or this has
been reported before. :)