Good on Delta. I can't stand the urine covered floors on most North American airline's aircraft. It is particularly bad in the economy cabin. People just pee wherever they want; on the toilet itself, the floor, the walls, wherever. Others leave the lavs a mess. The business class lavs are cleaner on the aircraft where the cabin lav access is restricted.
Appreciably some people are incontinent or have bladder control issues. I suggest that they consider;
1. Incontinence garments or;
2. Using the washroom prior to departure or;
3. Not consuming alcohol and/or caffeine infused beverages or;
4. Kegel exercise.

And to be blunt, I don't want people lining up next to my seat. On some transcontinental flights when I am in a row near the lav, it is irritating to have some of the slobs lining up, grabbing on to my seat or loudly yammering away as if my personal space doesn't matter.
I had one rotund women stand next to my seat who let loose an unending stream of toxic flatulence. On another flight I had a guy who kept belching a gag inducing awful stench. I feel for the folks who are seated close to the lav because they have to deal with inconsiderate jerks. In an ideal world, the lav lice would be banished to Spirit and Frontier. It's not fair to the folks who are paying a premium fare to have the lav line next to them. Mind you, it's not fair either for the comfort plus pax to be denied access to the forward lavs. They can't easily access the lavs in the back of the bus. Give them the access up front.