I saw mention of this build on discord so I plan to build it for my first 2E game at 5th level.
It seems overpowered in combat but I'm not sure what needs to be changed to fix it.
Part 1: At 5th level Rogues add 2d6 extra damage on strikes vs flatfooted opponents.
With less enemies having attacks of opportunity, Nearly all melee characters having close to the same AC, and Rogues having good HP, There is less risk for a melee rogue to move into flank then in 1E.
Of course without beating your opponent on initiative or having a flank buddy your best bet is Intimidating Glare and a lucky roll.
Also after 2 updates there is still no change to precision damage being doubled on a critical strike. Combined with the decreased progression of sneak damage it may be intended.
Part 2: Fighter Dedication at 2nd level and Basic Maneuver (Double Slice) at 4th.
For my Rogue the Fighter Dedication is just a feat tax but considering casters could cast in medium armor if they wanted to by just having 16 dex, And it allows several classes much better weapon choices, This feat may be too good.
Basic Maneuver seems fine on it's own assuming the level 1 and 2 Fighter feats are balanced.
Part 3: Double Slice using a +1 Rapier, Expert Shortsword, and Doubling Rings.
Two of the pregens are using Doubling Rings to effectively have 2 magic weapons so that is intended.
As long as your second weapon is agile Double Slice allows you to spend 2 actions for 2 attacks with no penalty.
All of the parts combined:
Move up to a flatfooted enemy. Either by beating them on initiative or by flanking.
Attack with your +1 Rapier and then your Expert Shortsword which is treated as a +1 weapon due to Doubling Rings.
Assuming 18 dexterity.
1 hit - 4d6 +4 dmg.
2 hits - 8d6 +8 dmg
1 hit 1 crit - 12d6 +12 dmg (+1d8 if it was the rapier)
2 crits - 16d6 +16 +1d8
With 18 dex and 2 +1 weapons vs a flatfooted opponent 2 hits seems realistic. 8d6 +8 is good damage at level 5.
2 crits is much less likely but an average of about 75 dmg will knock a big chunk off of any at tier enemy.
There are drawbacks of course.
In a 4 player party you won't always have a flank buddy. So you won't always be facing a flatfooted opponent.
With your hands full there isn't much you can do with your 3rd action. Move, Feint, or Intimidating Glare are about it.
And of course you are painting a target on yourself by dealing so much damage.
If one of your weapons has the Parry quality, you could use your third action to defend with it and get +1 AC. Later on you could take the fighter feat Twin Parry to do the same thing, or to increase the bonus to +2 with a Parry weapon.
(You could make a shield your off-hand weapon for the same effect, except it isn't finesse.)
If you don't have someone to flank with, then Feint is probably a good option to get the target flatfooted.
Possible issues with the fork idea.
1. The Doubling Ring only works if the second weapon is of the same quality. So the fork has to be at least Expert quality.
2. The ring doesn't add the potency effect if you throw the second weapon.
3. Throwing your weapon means you have to spend an action to draw another one unless you have a relevant feat. No more drawing weapons as part of your move.
You could still use the fork as your second melee dmg but I'd rather just use another shortsword for the bigger dice.
Then again, may not be called for. Double Slice does count as 2 attacks for MAP. And that is the result of a two feat investment. *shrug*
In case it isn't clear, "Make one Strike (see page 308) with each of your two melee weapons, each at your current multiple attack penalty."
If you haven't used a strike action yet then your first attack is at a penalty of 0 and the second attack is at a penalty of -2 unless it is with an agile weapon, In which case both attacks are at a penalty of 0.
The last line "This counts as two attacks when calculating your multiple attack penalty (see page 305)." means that a 3rd attack is treated as if you had made 2 strike actions instead of one.