Well here's the list of the main issues I can come up with having not seen the specifics.

1. Can you stack multiple traps on 1 square? Could I in theory set 100 traps on same square and 1hitKO anything?
2. What's the duration of the trap? Can a player set traps over a whole dungeon?
3. Does the trap count as damage by the player or the environment. If it's the environment then players won't get loot/XP or alternatively can manipulate XP so it all goes to another skill.
4. If it affects other players in a non-pvp environment then I could in theory set a trap in Fanrir's basement and see all the new players instantly die.
5. Does trap trigger if a mob spawns on it? Will it trigger if I set a trap and mob is already in trap range?
6. Can attunements boost damage?

As far as balancing goes I'm unsure what is best dmg value. Assuming an open environment and a 5x5 square then lvl/2 dmg per trap would be my initial value. Reasoning being that assuming a mob hits 5 traps in a row it's 275 dmg at lvl 110 putting it in line with storm spells. Having said that it's best case scenario and in limited space 55 dmg is not a lot so it might need boosted from that value or it will turn into a situational skill. I'll also note that there is potential to /push a mob around activating lots of traps.

I'll also note that if this skill does work well there could be potential to develop a thief/ranger style build with poison traps, paralysis traps etc

@smacky, sry never my intention to push. IDK why but  Hallowed Ground suddenly popped into my head and I remembered it so my first response was what happened to that thread...

@Shroud - Yes I agree with all of your list, we should do it!

BTW I get really schizo whenever anyone mentions a Thief class and I really really really hope it never even gets considered.
I belonged to a pay for MMORPG very much like Daimonin before I found my home here.
They had a thief class and it killed the community,
the game,
not to mention caused extreme hostility between players.
To put it in a nut shell players would spend days camping an item and the thief classes would wait by the city entrance and then immediately steal / pick pocket the item that you had spent days / weeks camping.
The Admins did realize the error and removed the thief class but not before shattering the game for which it has never recovered - just my opinion but a thief class is a very bad idea.

Lots of bugfixes and changes done today. It's probably a good thing I never got around to making the prayer accessible.

Well here's the list of the main issues I can come up with having not seen the specifics.

1. Can you stack multiple traps on 1 square? Could I in theory set 100 traps on same square and 1hitKO anything?
2. What's the duration of the trap? Can a player set traps over a whole dungeon?
3. Does the trap count as damage by the player or the environment. If it's the environment then players won't get loot/XP or alternatively can manipulate XP so it all goes to another skill.
4. If it affects other players in a non-pvp environment then I could in theory set a trap in Fanrir's basement and see all the new players instantly die.
5. Does trap trigger if a mob spawns on it? Will it trigger if I set a trap and mob is already in trap range?
6. Can attunements boost damage?

As far as balancing goes I'm unsure what is best dmg value. Assuming an open environment and a 5x5 square then lvl/2 dmg per trap would be my initial value. Reasoning being that assuming a mob hits 5 traps in a row it's 275 dmg at lvl 110 putting it in line with storm spells. Having said that it's best case scenario and in limited space 55 dmg is not a lot so it might need boosted from that value or it will turn into a situational skill. I'll also note that there is potential to /push a mob around activating lots of traps.

I'll also note that if this skill does work well there could be potential to develop a thief/ranger style build with poison traps, paralysis traps etc

1) No.
2) Currently set to 20 seconds The cooldown is somewhere between 4 and 5 seconds.
3) Player, so EXP works and is always given to DP
4) It only affects players if in PVP. In the event a player logs out while their traps are set, the traps will only be sprung by mobs regardless of PVP status.
5) The mob must step on the trap, or be put there by some function which checks move_check_on.
6) Yes. It's a "Spirit" spell (TODO: Not sure this makes sense) so you'd have to find a spirit-attuned item (does such an item exist?).