We can be "autoswitching into dud coins" because it is very possible that coins look very nice on paper (theoretically the most profitable) but in practice it could not be the most profitable, even by a long shot. The whole point of this pool is indeed to attempt to switch to the most profitable but perhaps some real-world conditions are coming into play that are not taken into account when calculating the most profitable coin on paper
There are some real world factors I don't take into account very well. One is that when we switch, we lose out on a few seconds of hashing. I've "tweaked" some specific coins to adjust for this, as to not switch as often to coins that are only going to be mined for 10 seconds then switch back.
Also, I'm sure it's the case that having that gap while switching is putting wear and tear on GPU fans, and creating system instability.
The real solution is to eliminate the gap.
If anything it's giving the fans a few seconds of rest, I wouldn't worry about that. I don't see why temporarily dropping the GPU load while switching would cause instabilities by it's self. It would be a coincidence for a system to crash at the same time, it would've eventually crashed on it's own without the coin switch.