Well, my first thought is that the Techno at my table has taken far more drain from threading (she's shy of anything at a rating less than 5) than from compiling or registering sprites.
Consider a Techno with Resonance = 5, Willpower (which is also your Firewall, so it's a bad idea NOT to raise this) = 4. Assuming a stream using willpower for Fading, that's a DP of 9.
Registering a Rating 5 Sprite, the sprite will roll 10 dice, and average ~3 hits, or 6S drain. The Techno will generate with DP 9 an average of ~3 hits, soaking half the drain.
Okay, he has 3S damage on his track. Given that you're talking 5 hours to register a Rating 5 sprite, I'm going out on a limb and saying that he didn't do this on a run, he's safely ensconced at home, or somewhere else he can rest. So, an Hour later, he makes a Body + Willpower test. He's not a tough guy, so he's only got Body 2, that gives him DP 6, with an average of ~2 hits, so he's down to 1S... if he can't run the Matrix with 1 stun damage on his track, he's not a runner. If he doesn't have a run that night, he's healed well before morning.
Mind you, that's on average, the sprite could roll high, and he could roll low. But, those are the breaks.
And frankly, consider the following: A hacker is only as good as the programs he brought with him on the run. If the Techno realizes he needs another complex form, he just Threads the darn thing. Same goes if his complex form is too "weak". Only have Stealth 4, going up against a tough node? Thread it! 3 hits on the Threading test and he's now a hacker with Stealth 7. Yes, he's risking 3P Fading, but soaking 3 points shouldn't be too difficult (in fact, the sample techno above would soak every point of that a bit more often than 50% of the time).
