Fallback plan? That looked crappy. I already made up a build using the DAI build calculator, and had this setup-
1.leaping shot
2.long shot
3.full draw
4.hook and tackle
5.poison weapons
6.stealth
7.evasion
8.elemental mines
Fallback plan didn't seem good, and I wanted poison weapons to make use of "tricks of the trade" duration and damage bonus to status ailments. Poison weapons was only going to be the basic unupgraded version though.
Note that I made a build for assassin too. Making a build doesn't mean I'm decided, I just like to know what I might do ahead of time. Speaking of which, I really do love that skill calculator. Makes build making easy.
Fallback Plan fell into a similar category as Flask of Frost IMHO. It was one of those skills I discounted until I tried it. I found that as a non-assassin Archer, I rarely used stealth. It did not warrant a spot on my very limited bar. However, every so often I'd find myself in a tight spot with low stamina. Fallback Plan is a reset. It's an oh crap button that costs no stamina. What's better is it saves me on using health potions / regen potions. Plus you can use it tactically. Set it down, run in and let them swarm you. Drop your mines, and before you die you use it to reset back (at a great distance, full health) and watch the fire works go off. Then hook and tackle in on the swarm you just created, and leaping shot 3 times. Sooooo much damage. Grab the +50 stamina necklace and with upgraded mines you drop 3 sets of them. It obliterates entire groups with a fire work display to boot.
Seriously though, why start a thread asking for advice about spec/builds you have not done, and then critique them as if you are an expert. You admit you have not played an archer assassin or artificer archer. Go try it. Replace stealth with it.
Or alternatively go do archer assassin which plays like this (stealth, full draw, stealth, full draw, stealth, full draw, stealth full draw....etc). Then you can have your wonderous 800% full draw that takes several seconds in animation time. Mean while I'll be leaping shot 3x with hidden blades and shield bash that can proc on each of them.