make note that prescience is still the primaris, but it's now a two warp charge spell which means you're going to be looking at 3-4 dice to cast it unopposed (and still have a chance to whiff) and more if your opponent is holding dispel dice. even more if he has bonuses to his dispel rolls.
a lot of the lores have a lot of good stuff, but dispel will be the balancer. if it's like fantasy, which i assume it will be, you'll get to see your opponent's cast (how many 4+s he makes) before you decide if you're going to use any dice to deny. if you see someone cast a 3 warp charge power with 3 successes and you have some bonuses, you won't even have to commit that many dice to dispel. if the rumored casting/dispel rules are true, i think you'll be denying a lot more spells per game than you used to with just the 6+ on offensive spells targeting your units.