Personally, I completely agree with you Chris, and even suggested removing Zend_Db. For me, whatever effort is required to map input choice selections onto selected plugin strings (first parameter of the factory method) is not better than the effort to require_once the adapter and then instantiate it.
I'm not sure I completely understand the problem and proposed solutions, but isn't it an option to support as much of the ways to instantiate it as possible (within the borders of sanity, of course)? E.g. do it both with factory and with direct instantiation (and with forks and hope ;) - and let the people use the method which they like better?
