I think making traps a bit more complicated to construct is a good idea, brings them up to the level of realism of the rest of DF, and in some cases can actually make the traps easier to use. Many people, myself included, consider traps to be too powerful for their effort, making defending yourself through actual military means unnecessary in all cases. Requiring infrastructure for traps helps to offset this problem, and making it so that this infrastructure actually takes space means that even a fairly thorough trap system will have some gaps that can theoretically require some military to cover.
This can bring traps up to the level of accuracy portrayed by the rest of Dwarf Fortress already. Everything from siege weapons needing to be loaded to irrigation make DF on the side of complex accuracy instead of simplification. Right now, traps are just magic squares that kill things. Stone-fall traps can be built under blue skies. I wouldn't propose making them too complicated, but the rest of DF takes the stance that you should have to plan a little bit to make something complex work; I don't see that traps should be any different.
So, I think that weapon traps should actually be 2x1. One of these squares should be impassable, essentially becoming a modified wall. This wall tile is what needs to be maintained. The passable tile is the trigger. Placed in a 6xN room, you can have a central corridor 2 spaces wide with trap walls on either side and behind them, access halls for maintenance/reloading. The trap should be able to be set as automatic (requiring power) or one-use, which would require a reset job by a dwarf. This means it would require a bit more material to set up (a block for the wall), and possibly the infrastructure for power, and finally would require more space. In the beginning of the fortress, the one-use option helps to keep the trap a solid defense when you cannot afford much of a military, but it can be overwhelmed, which is good. These can be easier to use once installed, since dwarven engineers do not have to wander out into the kill-zone to reset them (as the wall separates the access shaft from the target zone).
Stone-fall traps should require that they be built indoors. It's silly to have a device that drops a stone on your head out in the middle of a field (unless it's a catapult). Other than that, I see little reason why this should not be possible almost as it is now. Since it's not an automatic kind of trap, there's no reason why it should require power. If some desire is made to make these a little more complicated, then they could simply drop whatever is on the floor above onto the tile in which the trigger is set. These are, however, still somewhat too potent. So, given the predictable nature of these traps, and how easily they can be spotted and how slowly they're deployed (relying on gravity for propulsion rather than some controllable mechanisms), these traps should have a chance of simply missing.
Cage traps are the really overpowered ones. Absolute defense that also gets you a captive for the price of one mechanism and one cage. Honestly, what with the cages being free to be moved, I don't know how these traps are intended to work. The only way I can think of is that the cage is being propelled at the target (probably from above) and is locking into the sixth side. This would mean you could spot the floor of the cage on the trigger floor or the hanging cage above. This would require that the trap be placed indoors again, and there would be a very strong chance of the enemy simply dodging away. Cages built for specific sizes of creatures might be a good balancing factor. If the creature is too large for the cage, then it simply doesn't work. If the creature is too small, it can fit through the cage's bars. Terraria would be able to hold small creatures, but the breaking of cages would help to offset that strength.
Pressure plates that require complete reset should work as they do now. Pressure plates that work automatically should either require that the plate be powered or that the target item be powered (like a bridge, or floodgate).
Upright spike traps should require that the floor underneath be solid. In other words, there shouldn't be dwarfs running around under the spike trap, since they would have to weave between the unsprung spikes. I don't have much experience with this trap, but since they seemingly can only be used by attaching them to a control device, then they should follow the rules for that control device. If it's a pressure plate and they're set to auto-reset, then it should take power. Levers take power from the dwarf pulling the lever. If the spikes are constantly being triggered (i.e. a lever set to repeat pull), then they should be more easily avoided. Perhaps for every time in the last 200 time steps that the spike fires, there is a 5% greater chance of avoidance by whomever it concerns. This helps to model people being able to SEE the spikes shooting up and not just walking over them.
That's my two cents.