We looked at this and just don't think it's worth any time investment. The contrast against the background is high enough, and even against the regular text for ppl who can't see reds, there is what seems to us to be a fairly clear distinction.
Yes. This is a known consequence of the design of this feature, and the StackExchange team has indicated that they do not plan to fix it. The issue is that they cache this number, and the cache gets out of date. Also, they compute the total number of reviews, rather than the number that you personally can perform, because they don't want to compute it ...
The link colors look different enough, I think.
However, the core premise here (that we use visited/unvisited styles to indicate new answers on a post) is flawed. We don't.
With that in mind, I suggest keeping an eye on the questions list (sorted by active, so posts with new edits/answers/etc float to the top) instead of relying on the link color.