The thing to remember about the 1990s is that comic book movies still weren't being taken seriously, despite some glaring financial successes. I blame the 1960s. MAD! Magazine and the Batman TV show, with their bright pop colors and parodic attitude, led to a pervasive belief that superheroes were (and had to be) funny. Superman found a balance between comedy and drama largely due to Reeve's nuanced, inspired performance. The show in Batman was stolen by Jack Nicholson, and in Returns by Michelle Pfeiffer (never were Danny DeVito and Christopher Walken less needed in an overloaded story).
So Schumacher had a smaller world in which to work in 1995, and the knowledge that brighter and shinier seemed to be more entertaining than the darkness of the Penguin's grossly horrific tragedy. We hadn't had the Spider-Man movies, or Bryan Singer's earnest X-Men tone (which would work less well on his Superman Returns) yet to raise the bar. Now we know that mutants are a metaphor for the repressed underclass, that Spider-Man is every talented outsider trying to make his way in the world, and that superhero films can have universal themes that speak to a larger audience than comic book geeks.
But then all we saw were the silly suits. So Schumacher followed his instincts with those, and sexed them up. The one avant-garde cultural wave he was cognizant of was the increasing sexualization of the male form (underway since at least the mid-1970s) in American visual media, and was he so wrong that the Bat-family had its sexual side?
Neal Adams had revealed Bruce's real nipples and hairy chest back in the desert making love to Talia in the 1960s; many women had come and gone as sirens to occasionally distract playboy Bruce Wayne, and sometimes to attract the attention of the haunted, but emotionally needy Batman too. Selina Kyle was perhaps the lasting force (though too damaged in Burton's film to carry over), but Silver St. Cloud, Talia, a few others had made an impression.
Basinger's Vale was given little to do but scream in the first film, but Nicole Kidman's Chase Meridian (was she a Bond girl in disguise?) was a noble attempt at attracting Bruce's attention, a psychologist in a film at least superficially concerned with dual identities, with revealing hidden aspects of character, and exploiting personalities split to pieces by trauma.
Okay, maybe at most superficially, because none of those themes were deeply explored by the script. Rather, in an urge to duplicate that campy excess of Nicholson's Joker, Carrey and Jones vamped in even more outlandish costumes, chewing the scenery as oversized clowns whose hate for the Bat was a given rather than any deeper quirk that could be believably explored.
Two-Face's very visible division (down to his clothes, up to his hair) made him a refugee Dick Tracey villain, not really the focused sort of threat the Batman required. Jones was apparently demanding on set, the kind of behavior that can happen from a gifted actor if the script doesn't serve his character. All of the excesses that would lead to the toneless fourth film were present, but in Forever at least we had a cast capable of rising above the limitations of the story, and a coherent enough narrative that made the set-pieces entertaining, if never getting much deeper than all those gleaming sensual surfaces painted in such gaudy jewel tones.