Ouch, I got stabbed 14 times!
Yes, a rake has many bits, but too many bits to be remotely practical. Let's also be honest, a Trident was also never practical. But if you're going to make comparisons, do so with their direct equivalents.
Like the humble pitchfork. Pitchforks aren't really scary, either, and they're wielded by peasants, and have been over the years as a tool of necessity. They can be pointy, but not especially so. Yet still, many men have been slain by a pitchfork. A pitchfork, however, still isn't a Trident.
Tridents, in almost all depictions, are just spears with extra bits that have two extra prongs that curve inwards, then point slightly outwards, with the focus being the center-most point.
However, the two are vastly similar. One could argue, on the other hand, Tridents by their nature should simply be made a Simple Weapon, and their stats left alone. They're not very practical, they resemble a peasant's pitchfork more than anything, and pitchforks aren't as good at getting those critical bits as Spears are. So being a version of a spear that does 1d8 and 18-20 x2 instead of 1d8 3x would mean they could more frequently hit sensitive bits, but without doing it quite as well as a spear, when it finds it's point, because it's better designed and easier to use. There's no reason a Trident would be as light as a spear, because it has three times as many pointy metal bits. Make them two-handed if they're already not. That balances it out quite nicely, as you'd have to be a trident/pitchfork weaponsmaster with a two-handed 1d8 18-20 x2 weapon to actually invest in, and if powerbuilding was a concern, the rapier does the job better, one-handed. However, for people who want reasonable flavor, this still gives a trident it's place beside the spear.
The reason it would never be reasonably one-handed is because a Trident is unwieldy as all get-out, and has never been militarily used with one hand. A spear has. Before you say Roman Gladiators did X, that was a gimmick, and that's one instance in what was essentially a bloody theatre. For show, not for it's practicality. The net was often tossed and used to tangle, then the Trident would be used with both hands.
If you were going to give them Improved Disarm, then Whips need it across the board, too. Otherwise, it'd be silly.