To put my unimportant word here :) .... Well I think that it's good practice to separate core and 'satellites'. Like the gdata in ZF ... well everyone (at least I do ;) have it in libs folder but little % of users is using it. But removing it would do nothing bad to the rest. If I could suggest the ZF could have the core (like the controller, actions, mvc part, session, ...) and 'satellites' (gdata, ldap, openid). The thing is that if you upload 'satellite' you'll keep it working just that ... no more things.
We'll that's just me, and my few thoughts about ... P.S. Sorry Kevin for sending it duplicate to you :) I'm just hitting sometimes 'reply' button and this time it did wrong. -- Łukasz Wojciechowski