I think it would make developing new features easier, as they would be handled as seperate items without compromising the whole. Most programs already have in one way or another something like that on install. Look for example at winamp, at install you can choose to install with the media library and winamp agent, or without, or with just one of the two.
The autoupdate would know if you have a function installed or not, and if an update becomes available for a function you don't have installed, you don't need to update, which concludes to less bandwidth costs.
And I don't really think it would take much extra programming, because I think Plus is already build that way (with each function seperate) so Patchou would only need to extract each code and put them in in a different way
And if there is time to program annoying sounds in, why not this?
and @ toddy: I have no clue what you just said.