I've been reading a good deal of complaining about the "Perils of the Warp" mechanic in DH and have pondered some about what might be done for this. One solution I can up with was allowing the purchase of a Talent called "Sturdy Concentration" which may be purchased once at each profession rank where the character's Psy rating increases. (to a max of six times if the path the pc follows allows for lvl6 psykers)
The Talent would work as follows: Once per day, equal to the number of times you've purchased this talent, the Psyker cannot cause a "Peril of the Warp". He may still be required to roll for psykic phenomena, if he rolls a 9, but any roll higher than 74 on the Phenomena chart is simply inverted to determine the result. (or, if that is not possible, the GM may call for another roll, or use the outcome of 74)
Ex. Tina has a Psyker named Hatshepsut whom is a lvl 3 Psyker and has taken "Sturdy Concentration" 3 times. While entangled in a fight with Orks she attempts to manifest a power and rolls a 9; at this point - prior to rolling for an outcome on the Phenomena table - she must decide whether or not she is going to use the benefit of her teaching (the talent) and burn part her 3/day ability to prevent herself from achieving a Peril. She decides to do so, and good thing too because she rolls a 96 on the table. Normally this would mean she'd be off to roll for a Peril, but because she used the talent's effect she cannot go there and instead reverses the numbers on her roll and uses these to find her new outcome on the Phenomena table.
Tina may use this ability twice more in this day before having to fear getting a Peril.
This, I think, still allows for some interested effects to occur when psykers cast, but gives them them a possible "safety blanket" they can hold on to, so they can feel confident when using their powers. This also allows for the fact that higher level psykers are going to be able to handle more powers without falling prey to the warp than those of lesser skill.
At any rate, just a thought.