@Loeffel - the theory of it sounds good but I'm not sure how easy it is to implement in terms of the timing of plugins being loaded into Calibre, in-built versus custom plugins, handling of duplicate names etc. I'm hoping Kovid can share his insight/experience on that as to what would "work" with the current code and obviously support a change if it is thought appropriate to do so.
@theducks - haha, too funny. You know you could run from source if you don't want to wait a week, right? Besides, you guys are lucky that I have been taking a break from work for a while to put these plugin updates out so frequently. That will definitely change once I start work again. Plus by being in Calibre it means there is the possibility (however remote since all are busy with their own stuff) other Calibre developers could work on any fixes/additions rather than it just being the original plugin developer. So it wouldn't all be bad...
And yes it is only Plugin Updater and Find Duplicates that I personally see being directly added to Calibre sooner rather than later.