Winamp 5 displays TrueType fonts smaller than Winamp 3. So if you want to preserve the original look of a Winamp 3 skin when updating it for Winamp 5, you need to multiply the fontsize value of TrueType fonts by 1.3.
Dominator, whose startup crashes were fixed in
comment #2, uses a TrueType font in the title bars of Playlist Editor, Media Library, etc.
The size of the title bar font of these windows is defined in standardframe.xml. Open the file, find the groupdef of wasabi.titlebar and increase the fontsize from 13 to 17.