Yeah, Google doesn't keep stats for feeds which are not followed by someone in Google Reader. So a little over a week ago I added all of the feeds and this is the result. The values will obviously normalize the longer that the feeds are followed, but writing a script to do it manually would certainly be much more accurate.
Edit: Also, you would need to make the script run multiple times daily. The $wgFeedLimit is by default set to 50, so you would need to visit often to not miss updates. Bulbapedia typically has over 500 a day.