Thanks for the information, I have a few comments though :
There's visual ways to tell us that we are aggroed by something while we keep doing what we are doing.
On the other hand, there's quests where doors have been added long ago just because you could pike them at the entrance while sending the rogue for a 3 minute stealth fest.
2) That would be great, as right now for an assassin, you use your assassinate as the opening move of a fight, then you are stuck waiting for it to refresh ( if you can ) or you have to fight the normal way.
3) well reduce the cooldown... I you trigger it as the opening move of a fight, usually the fight is finished when you can use it again.
As for assassinating things it works as long as you are behind the monster... if you are flanking it or in front of it it does not work. ( at least that's how it works for my assassin )