Just come across this client (beta 10) and I really like it so far. Very nice. (I have been using 3DFibs and RealFibs in the past).
Some future improvements/ideas are below, but no doubt lots of people have their own ideas/must-haves :
On your move, add hints when rolling over your checkers to show which open slots are available. Also, it would be handy not just to show the value for each dice separately, but also the combined move, if that's valid. (GNUbg does this very well).
Checker animation is great (sorely missed in RealFibs) but can it be made even slower? My PC is a 3Mhz Pentium 4 and even at the slowest speed I rarely see what happened! Maybe it needs to move at a contant speed regardless of the distance travelled?
Something RealFibs does very well is to allow any combination of windows (shouts, chat, player list, system) to be viewed at a time. An option to hide the right-hand tabbed section would be handy when concentrating on the game. It's a shame to lose the chat window though.
To be honest I don't use the shout window when playing, only the chat window. Could that be moved to new tab, or made optionally visible when viewing the Chat tab?
On the player list, the 'First Name' tab is misspelled.
Don't always start with the System Tab selected - use the last one looked at?
The Match menu and the toolbar icons don't stay in sync.
Is there any sound? The preferences menu suggests there is? Would be good to pick up sound from external sound files (like GNUbg does) so it's easy to swap in new ones.
I found the layout of the current score, the match length and the pip values confusing. Perhaps I'm used to other systems where the names are both at the bottom - one on the left (with pip value and score) and the other on the right. The match length is in the centre. Not sure what other people prefer.
I love the look of the bitmap boards (but that also means it cannot be resized - or does it?) Could there be a reduced sized option (half-size to make it easier on bitmap manipulation?).
I don't know how to save a match? I've probably missed something.