I very much doubt it’s left up to the individual CMs at the attractions to decide how many guests to process in each line. The parks have managers for the managers as to efficiency
JMHO instead of the actual line access, it could be the flow/number of people in the EP lines causing things to back up.
things that may very well be inflating the EP lines…
1. Could be selling more day EPs than in the past
2. Influx of new visitors (priced out of market WDW faithful) increasing the gate of standby
3. Possible influx of those seeking/awarded disability access passes Which use the EP line
As mentioned above, Spring Break will be true test of how U handles their crowds.