There isn't a single word about ssh access in user manual.
ssh is for advanced users only.
Personally i don't care does WD support it or not. I just want my NAS to be much more just simple 'external hdd'.
Installing custom things is quite easy using 'apt-get' thanks to that it does run Debian Lenny.
About transmission.. never used feature packs and never will, but I believe that transmission you get from feature pack is not newest version. But is it possible to compile latest one yourself from source. I did it (version 2.13) and it works fine. Quite easy.. basicly just './configure ; ./make and if you need dependencies install them with apt-get or compile yourself and add that to PATH.
One potencial problem is that more you install custom stuff, more dependencies you need and your system partition fills out very quickly. I wish they have it at least few gigabytes more in size.