While in-game the chat area was not automatically selected. It would help a fast communication (if one is playing) if the textbox to enter chats would either be "activated by pressing a key like 'tab' or 'automatically selected as soon as the user begins to type'
lacking ability to directly match specific players (would require an 'open to requests flag' though in order to prevent undue botherances :D)
very limited automatching capabilities which do not interlink with normal seeks. (would need fics type formulae here)
Links opened in Client do not raise the browser window to the front. (Or the client tries to stay on top?) :-/ (winXP)
Warnings about impeding disconnection do not popup in the foreground (yes mayhap the client tries to stay ontop) :-/ (winXP)
Strange Antialiasing behavior paired with no option to customize Antialiasing of the Fonts. (only autowrapped text is appearing correctly antialiased, other parts of the GUI lack antialiasing) (only WinXP it seems)
Windows Clutter
No indicator in the custom game dialogue in which room the game is created. (if you switch rooms by accident before pressing ok it will change the room it is posted in)
No personal templates for custom games
No Timestamp indicator in chat
Chat history cannot be logged. On disconnect or Timeout chat history is lost.
Slow updating of games lists
Games and user list behave 'jumpy' (that means lines change positions)
Awkward selection of reading player info about people chatting in the room. (one needs to use the usersearch or the list on the right)
No rating calculation for 9x9 and 13x13 boards. Beginners who want to play 9x9 would not benefit from the good matching of players that a rating system provides.