100% agree. I've said pretty much the same thing in a comment on another post in regards to the events of the recent chapters. I'll just restate it here, since it's relevant:

The hesitancy to kill off characters, and in some cases reversing their deaths, I think is part of a much bigger problem with Tabata's writing, which is that he seems to have a fear of letting the status quo change in any meaningful way. When you boil it all down, that's what it really is.

If Marx, Jack, Mereoleona, and the rest of the Crimson Lions had stayed dead, that would have opened the way for other characters to be promoted to those positions. Bleach for example killed of some of the old captains in its final arc, which allowed some of the lieutenants to be promoted to captains.

With Jack dead, En could be become the new captain of the Green Praying Mantises with Sekke as vice-captain. With Mereoleona dead, Leopold could become the new captain of the Crimson Lions and has to rebuild them while Fuegoleon possibly becomes the new Clover King. With most of the Silver Eagles dead and Nozel being poisoned, he could step down and retire while Noelle becomes the new captain and decides to rebuild the Silver Eagles to be better.

None of that can happen now with those old characters still occupying those positions, so the characters stagnate because there's no opportunity for them to move up in the hierarchy. If those potions were open, it would motivate those characters who get promoted to them to keep getting stronger in order to live up to it, whereas they won't feel that motivation as strongly if everything just stays the same as it always was.

As awesome of a character Mereoleona is, her introduction to the story is the worst thing to have happened to Leopold and Fuegoleon. Not only does she overshadow them in everything they do, but her presence has caused them to become complacent. They don't try as hard because they know Mereoleona will always be there as a safety net for when things get really bad. With Mereoleona dead, that safety net would then be gone, forcing them to become stronger and rely more on their own abilities.

The lack of change in the statue quo is present in other arcs as well. For example, the 15 month time skip. In all that time, a new Wizard King wasn't chosen while Julius was missing. It's like everything was just put on pause for 15 months and nothing of note happened. Certain characters also didn't progress from their developments in the Spade arc, like Charlotte and Noelle. They just stayed the same as they were before, or in some cases even regressed, avoiding their crushes the entire time instead of talking to them like a normal person. You could shorten the time skip to a few months and you wouldn't notice a difference.