One your FAQ is half FAQ and half explaining why you sucked as a poisoner.
1.) Weapon nick is not ment to be a damage skill, like you indicated it gets the poison on your weapon into them much more efficiently then straight melee.
2.) Grenade is not suposed to land the poison often. Its a damage skill with the added bonus of sometimes poisoning. Further some ingrediants will make far more interesting and devastating grenades.
3.) Resisting poison is based on con and inherent resistant/immunity to poison.
4.) You said it correctly on the mind control bit and screwed it up on the last part, fear poison does not cause forget.
5.) You don't need to spam the concoct skill if you have poisons ready before people step into the area.
6.) While multiple knock out attempts reduce duration just failing one does not make landing the second immpossible by any stretch of the imagination.
7.) Once you clear the mid ranks thieves of any path are not super deadly just spamming trip while solo, you get a max of 4 attacks with weapons that are not overly difficult to defend against with crappy hp the window of people you will beat with just trip lag is not that huge.
8.) Dex plays zero factor in landing poisons from your weapon in melee. You get a chance each time you hit them to poison them so hitting them more increases the chance.
There was more but thats enough for one post.
In future FAQ's you should not talk as much about your failures with the class because it gives people the wrong idea, you seemed to have an idea of what a poisoner could do but were not flexible enough in your tactics to pull it off.