Shounen Anime has been praised in recent years for slowly but surely integrating female characters into the main plotline, shifting them away from their firm position in the background of the classic shounen before them (each of the 2000s-era “Big Three” of Naruto, One Piece, and Bleach feature at least one prominent female character in their main lineup of characters—Sakura, Nami, and Orihime, respectively.) The next generation rising up to replace those anime is largely undefined, although Boku No Hero Academia is at the moment the clearest contender for this spot, and not accidentally has a very large female cast, most of whom are on a comparable power level with their male classmates (except for Midoriya and Bakugo, who as the main characters are naturally a cut above by necessity of the genre.) Compare this to the classical shounen epics of Dragon Ball and Inuyasha, where the female characters are, to be blunt, decoration. Bulma is introduced by crashing her car into and subsequently shooting a young Goku, all of which is utterly ineffectual, and the remainder of the series follows this pattern. Her other contributions to the series include: flashing an old man for material gain (she “very humorously” does not know that she isn’t wearing panties for this encounter,) flirting with a desert bandit, and generally throwing herself around like a piece of meat to solve any problem which Goku cannot punch.
The modern face of shounen femininity, however, is ultimately identical to its predecessors, but in a more insidious fashion. I would posit that the rise of “masculine” traits in women—especially power, that gold standard of shounen worth—is directly correlated to those traits becoming more desirable amongst the otaku base (at least in America.) See the case of Haruno Sakura, one of the main trio of Masashi Kishimoto’s Naruto (1999-2005.) Sakura begins the series as a foil to Naruto and Sasuke, being clearly the most attentive and clever of the trio but ultimately useless in the conflicts they encounter—she literally does not defeat a single enemy unassisted, and arguably none at all. This garnered her a singularly unfavorable stance within the fanbase, and so as the series entered its second part (Naruto Shippuden [2005-2015]) Sakura was given a massive boost in physical power beyond the scale afforded most of the other cast in order to make her more acceptable to the fanbase. I would posit that this effect is replicated in other manga, simply omitting the first part (the unconscionably weak female lead.) Modern shounen has now reached a place where increased power and growing masculinity have become so closely tied that female characters are now being afforded a larger reserve of individual strength in order to make them more relatable to the otaku base (their being indistinguishable from the male cast outside of character modeling saves the viewer the awkward experience of trying to relate to young women as characters.)
This is not to say that femininity is a dead concept in shounen manga. Hiromu Arakawa’s Fullmetal Alchemist has several female characters deeply embedded in the plot, all of whom are drawn very much on model;characters are drawn to superhuman proportions in only a few cases. Alex Louis Armstrong is a hulking bara wet dream, but this is done exclusively for comedic value, where more traditional anime such as Dragon Ball Z and Fist of the North Star takes them very much as par for the course. The only other characters whose physical proportions are in some way superhuman are, in fact, not human—see the homunculi and Alphonse Elric for the better part of the series. The other characters are in the bustier range as far as character designs go, but they are proportioned accordingly and the camera frames them as action as opposed to pure spectacle, to borrow from Mulvey (1973.) The women of Fullmetal are completely inseparable from the plot, and the main cast is fully reliant on them in several different contexts—they, however, remain very much women. This effect, however, is almost certainly due to Hiromu Arakawa’s being a woman, which is a tragically rare phenomenon in the modern manga industry.
In short, while modern manga and anime does seem to afford a higher level of power and agency to its female characters, I suggest that this is all towards serving the otaku consumption model in a way not quite so obvious as the blatantly oversexualized models of One Piece and Fairy Tail, among many others.