Having said that...
I'm sad to read the Windows Client is deprecated because honestly it's easy to run Windows or Linux in a virtual environment. I played CL on Ubuntu with Wine and the Windows Client for quite awhile and it was a very nice experience and something any lay person could accomplish.
HTML5 may be cool (think of how many MMOs are browser only), but I wonder how hard things like click-toggles would be and just general browser instability/weirdness compared to a native app. I doubt I'd play on my iPhone/iPad, but that's probably just me. I like the "sit down, drink coffee (or BEER)" and just play on the desktop experience. Plus CL is very... mousy... might be weird translating right-click etc. to gestures or whatever... barf.
Making a "final" client build (v1050 sounds about right) and just seeing how long until things implode would a) alleviate the need to volunteer time to update every 3 weeks and b) keep the small, but dedicated rangers... er... players... happy for probably a lot longer than anyone thinks. I mean, really, why shut it down when it's been chugging along just fine for so long. So there won't be new areas (Quirks!?!), tell blades, Trevor Mort skillz etc. etc. It's still a fun game.
I, personally, don't think the effort is worth it trying to get a new playbase etc. It's much more a "how long can we keep this game alive" in whatever form... if only for future online bragging rights. Hey did you hear about that weird Mac MMO that's been online since the late 90s? How cool.
Having digested everything I've read so far it seems that it will ALL just boil down to:
Will AWOL Joe let it all go and give it (sell it dirt cheap) to someone who cares and can keep it going. It's all on Joe it sounds like. Go get'em ANN! You were always my favorite back in the day because of your responsiveness... now I know it's because you were paid. Haha.
PS - I'm just a nobody middle aged script kitty web hack, but please do let me know if there is any way I can help out.