Since it's a good place for psychic talk, here some stuff concerning psychic powers:
choose amount of dice
resolve perils if double 6 or more.
deny the witch
resolve power if succesful
So a one wound psyker dies if perils before the power goes off.Quote taken from Trasvi over from Dakkadakka.
Compared to 6th:
% chance to successfully cast with # of dice
WC 1 2 3 4 5 6 7 8 9 10
1 50.00 75.00 87.50 93.75 96.88 98.44 99.22 99.61 99.80 99.90
2 00.00 25.00 50.00 68.75 81.25 89.06 93.75 96.48 98.05 98.93
3 00.00 00.00 12.50 31.25 50.00 65.63 77.34 85.55 91.02 94.53
Chance to get perils (assuming double 6' needed for perils)
WC 1 2 3 4 5 6 7 8 9 10
0.000 2.780 7.410 13.19 19.62 26.32 33.02 39.53 45.73 51.55
Expect to see 3 dice for a WC1 power, 6 dice for a WC2, 8 dice for a WC3.
A ld10 psyker had a 91% chance, a ld9 psyker a 81% chance, a ld8 a 72% chance to successfully cast. All psykers had 5.5% of perils.
So to match a ld10 psyker from 6th casting a WC2 power you now need 6 dice. Netting you a 26% chance of perils. And your blessing can be denied.
And yes, Prescience is now a WC2 power.
3 masterylevels: D6+3 power dice. Average of 6.5 dice.
2.167 dice per warpcharge.
5 masterylevels: D6+5 power dice. Average of 8.5 dice.
= 1.7 dice per warpcharge
10 masterylevels: D6+10 dice. Average of 13.5 dice.
= 1.35 dice per warpcharge.
The more psykers you have, the worse they get. Having many mastery levels is very unefficient.
In 6th you are able to succesfully cast most powers, even with 10 psykers in your army. In 7th you will only ever cast very few powers.
The new psychic phase is a nerf to psychic heavy armies.
A lvl 3 psyker may now cast one WC1 power around the same chance as he could cast three WC1 powers before. That's two less powers.
If you want to reliably cast a WC2 power (prescience) with 5 dice, you have a 81% chance of succes. A LD10 psyker had a 91% chance to cast the power in 6th. That's a 10% difference! You need 6-7 dice now to have around the same chance of success.
With 5 dice you have a 19% (!!!) chance of perils with worse potential results. 6 dice is 26% and your chance at casting a WC2 power is still worse than a ld10 psyker in 6th.
Deny the witch may be very slim on a blessing, but it's there.
Malefic has some terrifying psychic powers and may be the only reason why mass deamon psykers may be good.
You can have many psykers and a big dice pool to throw at some important powers and have a high chance they go off. While doing so also getting a high chance of perils.
In 6th you had a high chance to cast any powers AND you could cast almost all powers you had at the same time.
Basicly in 7th, psykers are point efficient in low numbers, but get worse the more mastery levels you have in your army. But you get the advantage of being able to choose more powers and having a better chance at denying.
I think the new psychic phase is a good thing. Might be fun to poker around with your dice.