That's pure BS.
You mean it is pure coincidence that all the components that get pushed into the play services app are now closed source? (keyboard, location service etc. etc.)
How would it affect updatability to keep those components open source?
There is a reason to move these apps away from the "core" android: http://arstechnica.com/gadgets/2013/10/googles-iron-grip-on-android-controlling-open-source-by-any-means-necessary/