At the risk of sounding preachy or simply suggesting too many things, we might change how deterioration effects your shooting a bit. As it stands, misses are changed into critical misses, we can definitely ruin your day. This however, overwhelmingly troubles low level characters, and is less a problem for characters that often hit 95 percent of the time, which is a good part of "viable" characters. Deterioration is really more the problem because it means your gun goes away. That isn't bad, but not taking care of a gun can, and will get you.
In short, I propose that deterioration ought to cause guns to simply miss whether or not you actually hit at the same rate it causes misses to become critical misses. But wouldn't that be a nasty change to people who get all the guns they use from hapless, and easily farmed NPC's? It would be. And that isn't a bad thing. It would make characters that mainly crafted and repaired guns useful, because they could either repair, or make fighting characters guns that didn't fail horribly at inopportune times. (and it would be that with my proposal. the rate of "upgrade" to critical failure on a miss is about 16 percent at 80 det. while that would be unpleasant, it's sort of supposed to be. it wouldn't ruin you, but it would still be worth considering whether you really wanted to risk potentially missing that often by using a dodgy, busted gun.)
At any rate, making crafters really useful, as opposed to being dubiously useful only as a way to keep guns from breaking, minting ammunition, and making the odd desirable gun would be good in my mind.