I believe that as time has gone on, the sets have focused too little on the enemies of the wave. How many times has a wave been revealed and someone has made the “Oh look the ninja get a bike, a jet, a car, and a dragon” joke?
In the beginning, The skulkin and serpentine had a variety of vehicles at their disposal, while the ninja had a dragon and a vehicle.
The final battle was a much smaller wave than the first two, but it still felt like the ninja didn’t have too much up on the enemies.
In the following seasons, there are a handful of sets that focus on the enemies, but it is still early in Ninjago’s life and it doesn’t feel over done.
I think with the introduction of Legacy is where this sentiment came to a front. Because all of the first wave of Legacy, and most of Legacy to this day, are remakes of the ninja’s vehicles. And Core carries this legacy.
After Legacy we begin to see only 1 or 2 sets focusing on the villains per wave. These sets are the 1st or 2nd biggest sets of the wave, or sometimes both (Prime Empire, MotM)
That isn’t really a problem, after all they are the antagonists, why shouldn’t they get a big set to show off their power/biggest threat? No, the problem is that it is the only set the villains get. No ammasable vehicles for the grunts, no sets focusing on a minor villain, or giving much flavor to the main antagonist’s army (because they usually have one).
Looking closely at the first half, I do recognize this problem has been around since the Final Battle, however the villains would get 3 or 4 sets per wave. Additionally, with 1 of 2 yearly waves being taken up by Legacy/Core, the lack of villain based sets is exacerbated to 1 or 2 villain sets not per wave, but per year.
I would like to say I also consider sets that feature a villain vs ninja where they have comparable-sized vehicles as included in “sets that focus on villains”, so the Dragon Temple core set from the summer '22 wave counts as the 1 set from core that focuses on a villain.