Volume Four had finally come to an end.
As you could see, this volume was very long—roughly as long as the first three volumes combined. It took this book from under five hundred thousand words straight to a million.
Overall, I'd give myself a passing grade for this volume. No more than that.
Let's go over the specifics slowly.
First, regarding the protagonist's abilities: given his circumstances, if he had come into contact with the Mind Stone from the beginning, he definitely could have powered up even further. But I didn't do that. After the Phoenix Force level-skipping in Volume Two, he went straight from Delta to Alpha-level. That was already a huge leap. For him, consolidating his foundation was more important than continuing to raise his level. Otherwise, even if he reached Omega-level, he would only be a younger version of the old bald guy.
Everyone knew the old bald guy. Even as an Omega-level Mutant, he could still repeatedly get knocked out of his wheelchair, because mind control was just too extreme a power. If you couldn't one-shot your opponent, they would one-shot you.
So I believed that, for Miles, expanding the breadth of his abilities was more important than his ability level.
After being forcibly raised to Alpha-level at the end of Volume Two, his development of those abilities had actually been fairly mediocre. In a fantasy novel, that would be called "an unstable foundation and an unsteady realm."
There was no such concept in American comics, but it was more or less the same.
Of course, his strength couldn't remain stagnant in the story either, so this volume primarily focused on expanding the "breadth" of his abilities. In other words, his toolkit became fancier. Psionic Magic, technological equipment, the Spark of the Heart, the Phoenix Avatar...