On LAX-HND (and return) recently, I definitely noticed that the second meal in PE/Y is much smaller than it used to be. In one direction, it was just a small vegetarian pizza.
I also passionately hate the small arrival meal. I am often connecting on either end of the TPAC sector; at least if TYO-bound I could just stuff myself with an unhealthy amount of curry rice in the Sakura Lounge to make up for it, but if US-bound then I'm stuck trying to make up for it with cheese cubes in the Admirals Club.
I also had the misfortune of having to eat the small vegetarian pizza as the pre-arrival meal ex-ORD and I found it funny that the instructions on the menu included how the side rocket salad could be eaten with the pizza. (Presumably as in to use as pizza topping?) The MUJI mix-everything-in-a-box ex-TYO is at least slightly more entertaining and on-brand for JL, but the ex-US second meals are just depressing and is more or less what you'd expect as the pre-arrival meal on AA TATL in Y.
I too don't enjoy the weird mid-flight pastry, but I actually do enjoy Udon de Sky which seems to pair very well with the Prosecco!