Change acrobat sneak speed to a straight movement speed buff. Then add to each assassin core:
+10% sneak speed
+10% chance to hide from tremor sense/blind sight while sneaking
+10% chance to activate switches/levers etc without exiting sneak.
Nimbleness needs to add to dodge cap with each stack. Expire ONE stack at a time (not all at once.)
Deadly shadow: Also add +10 hide/move silent. +2 Assassinate DC. -10% threat.
Assassins trick needs to be quicker.
How long does the threat reduction last?
Stealthy: add +5/10/15% sneak speed
Sneak attack training: add -10% threat to each tier (but only to sneak attack training in the assassin tree.)
As others have mentioned, bleed and venomed blades scale poorly.
Venomed blades:
reduce cost to 1 AP per
1d4/1d6/1d8 per 5 rogue levels
Bleed them out takes to long to build up useful stacks. Drop the cooldown to 4 seconds. Increase bleed damage to
1d8 at rogue 5
1d10 at rogue 10
2d6 at rogue 15
2d8 at rogue 20
Good.
Raising the % is good. Add a second check against the assassinate DC: if below 30% the attack triggers an assassinate attempt even if not in stealth. If not assassinated, deal 500...
Killer needs to expire one stack at a time.
Measure the foe:
add 5% sneak speed per stack (yes, if you get all the sneak speed bonuses you will sneak faster than your normal movement, but these are assassins. They should "appear" out of nowhere. Speed is key to this and also just to keeping up with the group in todays game.)
Have the stacks expire one at a time.
Light armor mastery:
T1 gives 2 PRR
T2 gives PRR = 2/3 BaB +4
T3 gives PRR = full BaB +6
Knife spec:
This is a very narrow category of weapons. Keep it narrow, but boost the bonus. Some options include:
+1W
+1 threat range (assassins are very good at making accurate hits)(This would be a total of +2 threat)
+1 multiplier (this would be a total of +2 now)(I think the first two options are better for an assassin than this one though.)
THEN ALSO:
Work out TWF.
Work out the auto agro problems.
There are lots of great ideas posted in the rogue forum and I don't want to repost them all here, but there are lots of neat ideas for the stealth system and I even posted one about the assassinate system for crit fails and successes causing different reactions for the mobs.
Thank you for the feedback and being active in the thread.