The worst character lasting the duration of the Silver Age is pretty easy to pinpoint. Wonder Woman, aka Diana Prince, had a lost decade and a half. The stories from that era are so easy to lampoon and so tedious to read that it's hardly worth the effort. In 1966, DC tried a brief reversion to Golden Age style stories, but that didn't work either. So in 1968, we were assaulted by the "all-new, all-now Wonder Woman".
Steve Trevor's in a coma, the victim of an assassination attempt. Wonder Woman learns that the Amazons must "journey to another dimension" to replenish their magic, so she will no longer have her super powers. She must learn to fend for herself in the world of men. Fortunately, she meets an inscrutable Oriental named I-Ching, who teaches her the martial arts. Together they decide to tackle Doctor Cyber, the evil genius who plans to take over the world.
Wonder Woman's real role model in this instance was undoubtedly Diana Rigg, Mrs Peel from the Avengers. Unfortunately for DC, the secret agent fad was already on the wane as this series began in Wonder Woman #178, Sept-Oct 1968. The series also drew the short straw on artistic talent, as Mike Sekowsky was assigned to those chores. Sekowsky was easily DC's least interesting artist of that era.
In #180, we meet Tim Trench (could they be any more obvious with that last name--Trenchcoat, you mean?), who turns out to be Sam Spade in the Maltese Falcon:
In defense of Denny O'Neill, who scripted this, it's fair to assume that not a lot of people who were reading Wonder Woman at the time had seen the Maltese Falcon.
Steve croaks in WW #180, and although we get one bit of Diana kicking butt on his killers, that's pretty much it; no mourning of one of the longest running sidekick characters in comic history at that point. Steve was the male version of Lois Lane in the comics; the goofy foil who retains solid qualities.
Did I mention that Diana ran a boutique? Yeah, she became a real savvy capitalist; spending all her time gallivanting all over the world fighting evil and still somehow selling enough groovy threads to make a living:
Cute skewering of some aging hipsters there, and the plothole is not likely to occur to most of the readers of this mag at the time, even when they find this on the next page:
Well, of course let's go to Europe. After all, Diana's only living in a crummy apartment that even Trench wrinkles his nose at:
Okay, I'll ignore the obvious money problem from now on.
Doctor Cyber is dramatized a bit unfairly I would say. Check out this from WW #179:
But then we get the big reveal in WW #180:
Which gets even harder to square with this:
Okay, a man/machine combo who turns out to be a woman, but not apparently a machine. And suddenly Ching himself knows this:
Except that at the time, Ching has nothing to tell him other than what he was saying a few issues ago, that Dr Cyber was a man.
Reportedly, the feminists were not happy with the makeover, probably because Wonder Woman went from being a confident, self-reliant woman to a gal with two guys bossing her around. Trench was something of a male chauvinist:
And yet, inevitably:
No, it doesn't make you fickle, it makes you fall in love with total losers. In WW #182, Tim absconds with a batch of Dr Cyber's jewels. But not to worry, in that very same issue, Di meets and falls in love with Reginald Hyde-Whyte, a charming and wealthy Brit who of course turns out to be yet another rat.
Apparently the series went on for another few years in this vein before Wonder Woman returned to the red, white and blue swimsuit. I confess to lacking the fortitude to continue.
Update: Fortunately Marionette read the entire series.