24F is my favorite Y seat on the 321. I find the 3L/R FA to be way more annoying than the pax queueing for the lav. The FAs like to park on the 23E headrest, but cock their rear-end back toward 24F. Most annoying during boarding and deboarding. Conversely, I seldom have trouble with lav queueing at 24F. Likely because I generally have my legs far out in front of me, so they can't creep back into the well, they have to stay toward D/E. (But not to argue your overall point. Queueing for the mid-cabin lav happens multiple times on every flight, even when the aft lavs are open.)