Posted 14 November 2012 - 06:42 PM
If you're planning on using two traps as your slot skills, then go the full 30 points into Skirmishing to get both Trapper's Expertise and Trapper's Knowledge. If you don't want to invest this much into Skirmishing, then I would really discourage using a trap as a slot skill.
As for Hide in Plain Sight, I honestly think that it's something that shines more in PvP than in PvE. The nice thing about PvE is that you can easily know beforehand what you need. If you're running a dungeon and are getting to some trash mobs or a boss that knocks down, you can quickly swap in Lightning Reflexes or change to Hide in Plain Sight (assuming you have enough in skirmishing invested already) and then change it back after.
If you're mostly just farming events or something like that, then taking abilities like Trapper's Knowledge/Expertise and Piercing Arrows is way more invaluable than any defensive abilities since they let you tag more mobs, so it really boils down to what you plan on doing.