While I see Telepathy as a much deadlier discipline than I used to, many Divination powers provide the means to manipulate the statistics in our favor, something I think is invaluable in a game of dice. Some powers are much more desirable than others, but with a very good primaris and ways to use each result, on the whole rolling here is a very good idea.
Primaris: Prescience
Rerolling hits is fantastic for any combat unit. Since the best you can hope for is a 3+ to hit, it is common for many CC units' damage to bottleneck at the to-hit roll. Prescience also helps with throwing spears, shooting witchfire and buffing support fire, just like Guide. The range is shorter, but since the Council is likely to be in combat and benefits so much from this spell I take one in every game. The Council doesn't have enough attacks and can't afford to let potential hits go to waste. It works incredibly well when used with other reroll, buff and debuff abilities such as Enhance, Doom, Jinx and Misfortune. Example: 8 Warlocks charge with Enhance for WS5 and Prescience against Jinxed (-1Sv), Doomed, Misfortuned Terminators. 24 attacks, 20.2 hits, 19.6 wounds, 10.8 failed saves. Okay, okay so we probably won't have all those powers, but it's fun to consider what rerolling everything can do to a unit. And having even one or two of those rerolls makes a big difference.
Foreboding
If I were to roll on Divination this is not exactly what I would be looking to get, but I would be far from disappointed to land it. One of the best things an assault-oriented unit could hope to do against the Council is assault it and deny it the bonus attack for charging. Warlocks and Farseers have very few attacks, so each and every one counts. Getting assaulted this way could tie up the squad or get more Warlocks killed than we can afford to lose. The units that would be looking to assault you would be tough units and horde ones. Boyz, Tyranid swarms, Zombies, Terminators, MCs and the like all come to mind. With TL ShuCats we actually have some decent overwatch potential, but shooting at full BS could really put a stop to an enemy assault, or simply deter them from attempting in the first place. A full round of shooting would really hurt with all those pseudo-rending shots and even if the assault succeeds, the charging unit may be significantly weakened.
Forewarning
I can only think of two uses for this on a Council. The first would be to throw it up on supporting units nearby. DE allies, Warp Spiders, a Crimson Hunter, anything that can keep up with the Council and needs every bit of defense it can get. The other use would be to put it up when you use the artifact Spiritstone to reduce your Farseer's warp charge costs. He could get a different 4++ this way and then enter combat with guys who might hurt him with AP2/3. Pretty situational and most likely unnecessary, but I'm just stretching here to come up with a way to use a second 4++ on a unit that already has one. Depending on my support situation, I might be looking to swap this for Prescience.
Misfortune
Before the codex dropped this was by far my favorite power in Divination. I suppose it is still my favorite, but I feel that many damage sources that benefitted from this before are effective without it because of pseudo-rending. The Council, however, needs it as much as ever. In combat they still need every advantage they can get against units with good armor. Jinx and the Remnants of Glory can help, but in the event I don't land Jinx, I might be hoping to get Misfortune to help with heavy armor. The Remnants are nice and reliable if you want to spend the points, but they do cost a lot and Farseers without Death Mission don't have enough attacks. Misfortune ups the damage of the whole unit and anyone supporting. As I said for Prescience, I think it works best with any other powers that improve our statistical chances to kill the enemy. It works well against anything that will receive a save, including vehicles taking cover. On another note, the range on Misfortune makes it easy to use to help support units instead of just the Council. In my last game it was instrumental to my Dire Avengers and Jetbikers taking out some Screamers that would have otherwise been hard to remove. This allowed my Council to move on and collapse a flank of IG, giving me access to the Colossi that threatened my scoring troops.
As an aside, this is another benefit of slinging out a lot of different maledictions--no limitations on targets with regards to shooting and assault. It allows a deathstar unit to influence a lot of the board all at once, where most deathstars' greatest weakness is their inability to fight in more than one place at a time.
Perfect Timing
In my opinion, Ignores Cover has become one of the most important, most powerful special rules in the game. With 6th Ed. we are seeing a lot of units with stealth and/or shrouded. There are also a lot of Aegis Defence Lines in use. Pounding through 4+ saves with dakka is one thing, but firing on 2+ saves is just beyond pointless. Reveal can go a long way to helping against the stealth/shrouded units, but nothing beats simply bypassing the cover all together. I think this power works incredibly well in combination with Jinx because it becomes possible to reduce MEQs to sliced salami using the Jetbikes' shuriken catapults. Stacking Jinx on the enemy and ignoring their cover can have simply devastating results and it doesn't take much luck to pull this combo off. Depending on your army make up you could even split the Farseer with this off to a nearby squad of Fire Dragons or Wraithguard that has disembarked. Have fun surviving 10 Fusion Guns with Ignores Cover! On the whole I think Perfect Timing is great as long as you have units that the Farseer can actually join who can benefit from it. It improves the value of Jinx and our pseudo-rending a lot and provides versatility in lists that are packing units with heavy-hitting guns.
Precognition
This mini-Fortune is a little better for our Farseers than it used to be. Now that Farseers have access to decent weapons, it might be worth it to reroll with them. Another less obvious use would be to tank hits using a Farseer with this power. In the event that he fails his saves, heal him up with Renewer. If he gets hit with ID weapons, roll your Look out Sir and pray. But in that event you need to roll three ones in a row and have a good chance to survive. If I get Fortune first (and I tend to roll for it twice before going to Divination), I will probably swap this, but the protection it can provide may be worthwhile if I don't have rerolls on the whole unit.
Scrier's Gaze
In order to use this power, the Farseer needs to be on the board. So if anything benefits from it, it will likely be a part of the army that is not the Farseer's unit. Due to the cost involved in using a Seer Council, the rest of the army is typically small and fragile as a matter of course. As a result, if I put anything in reserves it is likely to be objective snatching WRJs. I want those things off the board just about as long as possible. Sometimes if they come on, I use them for a little backfield support when the enemy has few other units to harm them from range. Usually though, I am happy to have anything that will help me try to keep them in reserves. Scrier's Gaze might be able to do that. But so does the number four result on the strategy warlord traits (I've rolled that three games in a row. Weird). This is a power that in many cases I would probably drop for Prescience. But if I am really depending on my reserves coming in late against an army with say, 3 Colossi (as in my last game), I'll be glad to be able to keep them off the board.
Divination is probably the most reliably useful of all three available disciplines. The Primaris is amazing, as are most of the chart results. I recommend always making sure to take at least one roll on Divination just to get Prescience as it is just too helpful in combat when unbuffed Warlocks have pretty unimpressive WS for their cost and number of attacks. I'd be likely to spend more rolls in this discipline in two instances. First, if I get Fortune then I will want something good that definitely costs only one warp charge. Divination has no powers that cost two, whereas Telepathy and Runes of Fate have a few each. Second, if I fight against an army like Space Marines or Chaos Daemons then Terrify doesn't enable me to perform sweeping advances. It doesn't do anything at all to Chaos Daemons. Against Marines, they might run off the board if they are close to it, but ATSKNF really hinder's the best uses of Terrify and some of the other Telepathy results don't compare as well to Misfortune, Perfect Timing, Prescience, or Forboding. Judging what you need based on your army, your opponent and what your Warlocks get is key (did I say always roll them first? Do. They only have one option and it's very helpful when deciding with the Farseers to know what the Warlocks have). Perhaps even more so than other lists, it is important to consider these variable factors when rolling because the Council is much harder to use without Fortune. In the case that you don't get soon, you have to consider the possibility you won't have it at all and plan accordingly to bolster your defenses and the efficiency of your offense accordingly.