The concern about PE using the WCs and walking through the mini cabin is somewhat moot.

When sitting in 1A or 1K you have a lot of pax walking past you to get to the WC at the front. In the mini cabin you have fewer biz class pax walking past you, but some from premium.

I have never had an issue with foot traffic in either spot. Six of one, half dozen of the other! (And yes, on almost all flights premium eco pax are invited to use the biz class facilities, it’s not a case of them sneaking in!)

1A/K are great because you get served first during the initial meal service, but you get served last for the second. If that second service is breakfast you can find yourself with as little as 15 minutes to eat before they start to prepare for landing. That’s fine for short overnight flights, but on the long hauls it can mean you are awake and kind of waiting with nothing to do.