The subject of Zeitgeist eventually replicating functionality presently offered by BWS has come up and I thought maybe I should comment. There are at this time no firm plans beyond those already described in this thread. After that, who knows? But, personally, I have little interest in BWS-like functionality. I have some highly tentative plans for quality of life features suitable for maintaining more curated mod sets, but it should be emphasised that these are highly tentative and will come after the already planned features have been implemented.
But Zeitgeist is free software using mainstream technology and if someone wants to contribute good code towards their cause, I'm not opposed to merging it.
Edit: also, on the subject of plugins: if there is demand for such, we can certainly talk about it, but there are some technical hurdles involved. The plugin would need to be compiled against the same versions of the same (relevant) libraries as the main program. Then there are whatever limitations are imposed by the plugin API. I'm thinking if someone wishes to write features for Zeitgeist, it might be easier to just upstream them.