I mostly agree with @MektonZ, however I don’t necessarily think that the character of Batman has been tarnished over time.
Yes, Batman’s over-preparedness and endless arsenal of Bat-Gadgets and Bat-Mechs removes the character from his roots as a crime noir vigilante detective. He has become what I think was inevitable the moment he joined the JLA: a superhero.
The modern Batman operates in a universe where he is constantly outmatched by beings with superpowers. He spends a good chuck of his time on a space satellite with aliens and gods and people in colorful costumes fighting giant monsters and intergalactic despots.
This is far different than his earlier Golden Age and Bronze Age adventures as a grittier dark avenger fighting against crime syndicates and thugs with tommy guns.
And maybe I’m speaking out of turn here... but isn’t that the point?
Batman began his career to fight the Joe Chill level criminals and their bosses. Then he starts fighting colorful psychopaths like Joker, Two-Face, and Riddler. Then his villains start having superpowers or science-fictional gadgetry, like Mr. Freeze, Clayface, and Poison Ivy.
The moment Batman stepped into the larger DC Universe with Superman and Wonder Woman, could we really expect him to stay this grounded crime-fighter when he’s staring down Darkseid?
In that, I feel like detractors from modern Batman could argue that the worst thing to have happened to the character was integrate him so completely into the larger DC Universe. Instead, he should’ve remained tied to Gotham with the occasional team-up here and there.
But personally, I enjoy a lot of Batman’s modern Herculean adventures. I think they’re fun and entertaining. I don’t pretend that they are realistic for a second, but they don’t have to be.
And I do think the character has a rich enough history that a single era or depiction cannot be objectively pointed to as better than others.
I certainly don’t have the heart to tell a kid holding a Batman action figure wearing Mech-armor “That’s not how Batman is supposed to be.”