im not encountering the black screen bug that snake mentioned, i am using V1.60 at the moment. i have however found some things that could be changed for the next release.
firstly on the login screen these links dont look very readable
- forgot your password
service status
sign up for a windows live id
privacy statement
windows live id
this is shown in the screenshot below.
also on the login screen see those boxes you turned green, i like the effect but you cant read the email address in the first box and cannot hardly see the stars in the second box maybe change their text colour to white.
now onto the contact list, the contacts groups have white text on them but if you expand them and your not using coloured text for the nicknames your giving to your contacts then in places you cant read there names very well, im sure you can change text colour to white there too, same applies to default text colour of names in the toasts.
final issue and this is huge, i dont think your advanced enough as a skinner to take this one on just yet neither am i by the way, is to reskin elements of messenger plus, you see in the convo window i have tabbed chats in my skin with light background the default black text is ok but not in your skin with dark green so at some point when your advanced enough at skinning to attempt it maybe change the default text colour used on the tabs generated by messenger plus.
thats all i can think of for improvements at this time.
EDIT:
if the tree background is turned on the first 4 links in the list look ok in white but if the tree background isnt on you cant read them, you could probably use a PlusSkin tag to change text colour based on with tree is on or off, the tes in the green boxes and for windows live id though has to be black or something in both instances.