I mean, that's kind of hard to redeem or do anything constructive with right there. The squick-factor on such a character pretty much reduces your available avenues to either screwball comedy or outright body-horror. Now, I know which I prefer, but let's explore both avenues in the interest of me being bored.
First off, going the humor route with a case like Mandrill is going to be tough. On the face of it, his power just ain't that funny-he subdues and dominates women. But, with the proper context, you could likely wring some bawdy fun out of things. Maybe Mandrill decides to go into black market couples counselling, selling jars of his sweat to troubled spouses in order to reignite the flames of passion. Or maybe he gets hired by a parody of the Axe Body Spray guys, who want some Truth in Advertising. You could even have Mandrill as an inadvertent Lothario, attempting to lay low or commit his crimes while being pursued by women that he has no interest in, including super-heroines who show up, drawn by his pheromones, just in time to foil his crimes.
Granted, this reduces Mandrill to a joke character, but frankly 'Rape-Baboon' isn't any great shakes as it stands. Better to be funny, than offensive to a segment of your audience, right?
Or maybe not.
If you were of a more unpleasant frame of mind, you could go the opposite route with the gentleman in question. Remember my post on Mr. Hyde? There are some characters who are built for nastiness and MAX situations and Mandrill is one of them. The writer could play up Mandrill's utter inhumanity to great effect in this instance, making him a truly nightmarish figure. The animal lurking inside every man, the abuser you can't help but love, the incestuous father/uncle/brother. Something that makes the reader cringe. He'd be a vile, disgust-inducing nightmare of a character.
Especially if he got away. Again and again. Always slipping away thanks to his abused coterie of followers. The eternal victimizer, never being punished, always lurking. The pay-off, when it finally came, would be amazingly cathartic. Granted, you'd have to put Mandrill in a box for a year or three before you could use him again, but as literary weapons go, he'd be a useful one. Foulness personified, and with a deft touch he'd make for a compelling (if unpleasant) story.
Unfortunately, I believe that there's no such thing as a deft touch in comics these days, and what you'd end up with is not a horrifyingly compelling villain, but a slobbering sex-bully in a monkey suit. He'd wind up an excuse to give the readers a lot of T&A and degrading situations to toss the token female character of the month into. Less a character and more an ambulatory plot device.
Which is why, in the end, I believe that to rehabilitate Mandrill as a villain, you have to remove his power. Or, at the very least, alter it. Make him able to manipulate both men and women, as opposed to just the latter. Or give him the ability to control the 'monkey-brain' of his victims, reverting them to savagery (I know, I know, that's the Lizard's schtick now, but monkeys are different to lizards, so shut up). Even better, make the effects of his pheromones more subtle. Like hypnosis. His victims do what he wants within reason, i.e. nothing they wouldn't ordinarily do. Have Mandrill ditch the disco outfit for a power-suit and make him Marvel's version of Gorilla Grodd, manipulating the stock market or bank managers or even the population of a town. Make him interested only in his own comfort, using his mutant abilities to simply provide for himself, rather than indulging in sadism or humiliation.
Basically, remove the squick-factor, and you've got yourself a relatively plug-into-plot character with an interesting power set and cool visual. And in the end, isn't that more preferable to 'rape-baboon'?