We're currently experimenting with a pretty radically different system for psychic powers, but an idea that's come up is to base the severity of problems on how much psykers have been pushing themselves, and it occurred to me that the basic idea can easily be applied to DH1e. So..

• When you use psychic powers, add up the Power Thresholds.
• Until the Thresholds adds up to your Willpower Characteristic, you change all Perils rolls to Phenomena rolls instead.
• Once the Thresholds meet or exceed your Willpower Characteristics, change all Phenomena rolls to Perils rolls instead.
• Decrease your accumulated Thresholds by 1 point per hour.

Aren't novice psykers sort of supposed to explode if they **** around with the HOLE TO THE WARP in their head?

I've ran a campaign well into Ascension now and I'll say this much, in normal circumstances a psyker who manages to acquire enough talents to control his psychic abilities and enough Psy Ratings to manifest his powers reliably on "Fettered" strength doesn't face nearly these kinds of problems. Taking the long view, I figured this was by design - if you survive long enough to control your powers, it pays off dividends in the end.

Aren't novice psykers sort of supposed to explode if they **** around with the HOLE TO THE WARP in their head?

I guess it depends on the fluff you're looking at. But in my opinion? No, sanctioned psykers shouldn't get into Perils table territory barring the most extreme circumstances. The raw power of sanctioned psykers varies wildly, but their ability to control it is usually pretty good.

Then again, PCs don't really behave like the fluff. Fluff personalities don't usually go from zero to hero, and even when they do it's nowhere as gradual, nor does it take them from and to the same ridiculous extremes as the power curve of the core 8 ranks covers - never mind the extended power curve of Ascension.

There's also the playstyle aspect. Psykers randomly going nuclear adds tension to the game, however little it reflects the fluff.

I'm not a huge fan of randomly nuclear psykers. I'm a big fan of psykers having the potential to go nuclear, but only if they're asking for it.

I'm also not a huge fan of the zero-to-hero PCs, by the way. I prefer my PCs to grow in influence, not prowess. Which, just like the psyker thing, isn't how the game system is set up. Thus: house rules.