So I've started running with my sixth character (Medium Armored Gunner with a focus on Crafting, Stealing, and Traps), and it's given me time to formulate my thoughts on the current state of Traps.
Personally, I almost entirely ignored the Traps skill on my first few characters - at least until I reached Junkyard. At that point, after exploding a dozen or so times, I re-evaluated my need for the ability to disarm traps. Given the curve, the Traps skill is still forgiving enough to be used as a lower secondary skill (I think you can disarm most of the mines encountered with a skill of 50-60).
At the moment, there are only three types of traps (EMP Mines, Frag Mines, and HE Mines) in five grades of quality. All three are craftable, with fairly simple recipes that closely resemble the recipes used for grenades (albeit with larger quantities of explosive required). Properly assembling mines requires a mixture of Mechanical and Chemistry skills (or Electrical when crafting EMP Mines).
Using traps gets a little trickier. It either requires foreknowledge of where a patrolling enemy will be going, predicting where a stationary enemy will move once combat begins, or using a high level of Stealth to plant a mine near an enemy. A secondary concern is, of course, moving away from the mine quickly enough to avoid being caught in the blast radius. For most light-to-medium armored PCs, a single mine of the lowest grade can often mean instant death.
With that in mind, the first thought is to increase the variety of traps for other tactical situations. As it currently stands, there are no low grade traps - Mines are expensive and dangerous for a beginning character, and they aren't encountered at all for the first three or four story missions. A good starting point might be something like a 'Snare' or 'Bear Trap' type of trap.
A snare-trap would be single-target with a temporary immobilizing effect, but causing no damage. A bear trap would be similar in concept, causing a temporary immobilizing effect in ADDITION to causing damage (and possibly bleeding?). The added benefit of a bear trap would be that, from a crafting standpoint, there are already scaling components (ie, Serrated Blades) that could be used to make varying levels of bear traps (with higher qualities causing more damage or immobilizing for a longer time?).
Then there are potentially other types of traps that cause damage other than mechanical. We have EMP Mines for use against Sentry Bots, but there's no reason you can't run further with the idea of specialized explosives. Incendiary or Napalm Mines would be easy to implement (as would Incendiary Grenades), using the Magnesium or Napalm C items from a crafting standpoint. The potential utility would be for a grenade/mine that causes less immediate damage than a Frag/HE explosive, but has a high chance for causing ongoing Fire DOT with the attached Fear/Panic effect.
On a similar note, there might be some potential for a Molotov Cocktail type of grenade (using the Gasoline component, and maybe a Flask?). It might be used as a low-damage grenade that leaves a small, lingering field of fire (similar to the Acid effect seen on Mutated Dogs). From a cost standpoint, a single unit of Gasoline and a Flask might be too low, so multiple units of Gasoline (or maybe a few units of Fabric Scraps) might work better.
Beyond that, there's the potential for other exotic traps or grenades (along the lines of the Chemical Blob Trap, which I completely forgot about). Poison-spraying traps. Flashbang Traps. Freezing Cryo-Traps. Shrapnel Traps (causing bleeding damage?). Maybe even some kind of psi-negating traps, that damages or blocks the psi-abilities of those caught in the blast?
There's also some potential for alternate components. Maybe an Optional Slot on Mine Blueprints, where different types of detonators can be fitted. A proximity detonator might allow a mine to go off when an enemy passes within two or three spaces, instead of moving directly adjacent. A timer might disable the adjacency trigger entirely, causing the mine to go off after five or so seconds instead. A camo tarp (or something similar) might make it harder for an enemy to detect the trap - although I've yet to actually see an enemy try to avoid or disarm a trap.
In regards to Feats, there's also a few potentials that spring to mind. At the moment we only have the Trap Expert Feat, which allows the PC to plant traps more quickly (with a reduced detection chance). Other potential Trap-oriented Feats might include:
Catch! / On The Fly: An active Feat that grants the ability to plant a trap during turn-based combat mode. Allows the player to drop a trap to cover their retreat, or to go out in a blaze of glory. High AP cost and/or Cooldown to prevent abuse.
Cautious / Watch Your Step: A passive Feat that increases the player's trap-detection skill, or that gives them a set percentage chance (maybe scaling with their Agility or Dexterity?) to not set off a trap when they stumble onto it. Provides an option for avoiding traps more efficiently, even without sufficient skill to disarm them.
Demolitionist / Precision Placement: A passive Feat that improves the damage or grants a crit-chance to traps the player plants. Effectively a similar Feat to the 'Three-Pointer' Feat, but used with traps/mines.
Duck and Cover / Hit the Deck: A passive Feat that increases the player's Resistance/Threshold against damage caused by explosive Traps and/or Grenades. Maybe it prevents the player from setting off his own traps, or provides an additional degree of resistance/threshold against their own traps?
Finders Keepers / Waste Not: A passive Feat that decreases (or eliminates) the additional difficulty to Traps checks in regards to recovering a disarmed trap. Maybe it applies a fixed percentage chance of trap recovery, to prevent an excess build-up of cash from disarming. An alternative might be recovering components instead of a full trap (mine case, explosives, etc.), when disarming with insufficient skill to recover the trap intact.
Red Wire, Blue Wire: A passive Feat that allows the player to disarm traps more quickly, in addition to another minor effect. Maybe it prevents a critical failure from detonating a mine? Maybe it slightly reduces the disarm difficulty?
As a final note, I would suggest a new component for Goggle/Helmet crafting. Polarized Lenses. Fighting Sentry Bots can be a huge pain, due to their Flashbang grenades, so an optional component that increases resistance to Flashbang-induced incapacitation would be welcome.