The Forsaken are some of the most powerful channelers ever born. They built monstrosities and unleashed literal evil upon the world. We are told that they did things so heinous they are nightmares 3,000 years later. With what we know of channeling back then, these crimes are easy to imagine. Plagues, torture, annihilation.

However, in the present age, most of their schemes are useless. Just about every time they go up against one of our heroes, they lose. Untrained, Rand beats the most powerful, Ishamael, three times in the first three books. The most substantial blow a Forsaken lands is Lanfear's assumed murder of Moraine (but Lanfear is killed and substantially weakened too). They do twisted things like binding people into absolute servitude, but this never happens to characters we care about nor is it something we really fear. In most instances, the Forsaken act like side quests. We went to Tear to get Be'lal, to Caemlyn to get Rahvin, and to Illian to get Sammael. Messana is just one small thread in Egwene's white tower hunts.

The worst part is that so few of them die and remain dead. Ishamael dies/is defeated in three climaxes in a row. Lanfear comes back after her 'death', and so do those forgettable two from book one that our party killed instantly. (Their names are Balthamel and Aginor but the fact that I had to look it up says something) Graendal also dies and comes back. Defeating the same enemy over and over does not increase the stakes, despite Robert Jordan's writing skill. We already know the outcome as we've seen it happen before.

The classic argument is that being displaced in the Third Age removes them from a lot of their sources of power. This makes a lot of sense in terms of world building. If 90% of modern humans were tossed into the Renaissance era, we'd be lost too. Their tools are missing and broken. Their incompetence is well justified.

It is a bit boring, though.

The show was on track to fix most of these problems. Several of the forgettable Forsaken (and their resurrections) were cut. Ishameal smiles when Rand 'defeats' him in Season 1 Episode 8, and he has dealt a major blow to Moraine. It sings of a false victory instead of a success as in the book. There are other moments that sing evil so much more than the books. Lanfear tortures Egwene with nightmares of being a damane. Moghedien steals the scene every time she shows up: the grey man scene. She also lands a powerful blow against Nyneave and Elayne. I would be surprised if there was someone who wasn't scared of (or at least creeped out by) Moggy. Every single villain had a presence in the show.

However, in the end, who stands to face Rand, who stands to challenge the Dragon Reborn during the Last Battle? Rand faces the Dark One outside the Pattern, alone. The laughable Forsaken aren't there. And it is not a battle of power. The Last Battle is a battle of choice. The Forsaken do not matter here. What they do or don't does not matter. It is the choices of the people to fight and choose the light that matters. Rand makes his choice to seal the Dark One away because of his friends' choices to fight for a better world. Rand is not thinking about what the Forsaken are or are not doing during this moment. The Forsaken are meaningless villains both meta-textually and in-world.

The show was sadly cancelled, so we shall never know it's full interpretation of the Forsaken.

tl;dr