TLDR:
Prowess is still ahead significantly, post nerf AFAIK. Even if you go for full MP set-up (which scales your damage the best), you're still behind by 10 MP and you lose that 11 PRR and the 2 action boosts.

Someone else can propose an optimal non-prowess set-up. With Sharn's 9th slot, we'll just pop in another Sucker punch Melee rare for an additional 10 MP on the prowess set-up. The current nerf of 12.5  melee power (on average) will be undone.

~

Prowess U41 Set-up

1. Prowess, Melee Power: +3 Melee Power (Rare: +2 Melee Power)
2. Prowess: Attack and Damage      +1 to hit and damage      +2 PRR
3. Prowess: Critical Confirmation and Damage: +2 to critical confirmation rolls and damage (Rare: +2 PRR)
4. Prowess: PRR      +3 Physical Resistance Rating (Rare: +2 MRR)
5. Prowess: Strength      +1 Strength (Rare: +2 PRR)
6. Spines of the Manticore/The Wreath of Flame, Raid Filigree: +6 Melee Power (Rare: +4 Melee Power)
7. Sucker Punch/One Against Many, Raid Filigree: +2 Strength (Rare: +4 Melee Power)
8. One Against Many, Melee Power: +3 Melee Power (Rare: +2 Melee Power)

One Against Many 2 Pieces: +5 Melee Power
Prowess 2 Pieces: +5 Physical Resistance Rating
Prowess 3 Pieces: +5 Melee Power
Prowess 4 Pieces: +2 Action Boosts
Prowess 5 Pieces: Gain +50 Melee Power for 10 seconds when an action boost is used. (25 MP avg)

Total
59 Melee Power (avg)
1 to hit and damage
3 to Strength
2 to critical confirmation rolls and damage
11 PRR
2 MRR
2 Action Boosts

Proposed U41 Melee Non-Prowess Optimal Set

1. Spines of the Manticore/The Wreath of Flame, raid filigree: +6 Melee Power (Rare: +4 Melee Power)
2. Spines of the Manticore: Attack and Damage: +1 to hit and damage with all weapons (Rare: +2 PRR)
3. Sucker Punch/One Against Many, raid filigree: +2 Strength (Rare: +4 Melee Power)
4. Sucker Punch, Melee Power: +3 Melee Power (Rare: +2 Melee Power)
5. Sucker Punch, Attack and Damage: +1 to hit and damage (Rare: +2 PRR)
6. One Against Many, Melee Power: +3 Melee Power      (Rare: +2 Melee Power)
7. Treachery, Melee Power: +3 Melee Power (Rare: +2 Melee Power)
8. Treachery, Critical Confirmation and Damage: +2 to critical confirmation rolls and damage (Rare +2 PRR)

Spines of the Manticore 2 Pieces: +2 Damage
Sucker Punch 2 Pieces: +5 Melee Power
Sucker Punch 3 pieces: +1d6 sneak attack damage
One Against Many 2 Pieces: +5 Melee Power
Treachery 2 Pieces: +5 Melee Power

Total
44 Melee Power
2 Strength
1 to hit
3 to damage
2 to critical confirmation rolls and damage
3.5 Sneak attack Damage

There is no 10 MP filigree on live. It was a lamma thing.

If you're dex-based then you want to do the treachery 3-set for +2dex maybe.
I agree that sucker punch (or treachery) 3-set is BIS atm.

If you are desperate for PRR or Healing amp, then the raid filigrees aren't bad (10 prr, and 20 hamp respectively).

With a 9th slot that becomes:

Spite set 1: Deadly Rain
Deadly Rain
2 Pieces: +5 Ranged Power
3 Pieces: +2 Damage
4 Pieces: +3% Chance to Deflect Missiles
5 Pieces: When you use an action boost, gain +20 Ranged power for 20 seconds

Deadly Rain: +1 Dexterity      +2 PRR
Deadly Rain: +3 Ranged Power      +2 Ranged Power
Deadly Rain: +1 to hit and damage      +2 PRR
Deadly Rain: +2 to critical confirmation rolls and damage      +2 PRR
Deadly Rain: +3 Physical Resistance Rating      +2 MRR

Spines of the Manticore
2 Pieces: +2 Damage
3 Pieces: +3% Chance to Deflect Missiles
4 Pieces: +10 Ranged Power

Spines of the Manticore/The Wreath of Flame  +10 Ranged Power
Spines of the Manticore: Ranged Power      +3 Ranged Power      +2 Ranged Power
Spines of the Manticore: Dexterity      +1 Dexterity      +2 PRR
Spines of the Manticore: Attack and Damage      +1 to hit and damage with all weapons      +2 PRR


Spite set 2: Nystul's
Nystul's Mystical Defense
2 Pieces: +5 Magical Resistance Rating
3 Pieces: +1 to all saving throws.
4 Pieces: +100 Hit Points
5 Pieces: Your Max MRR Cap is increased by 40.

Nystul's Mystical Defense: +1 Constitution      +2 PRR
Nystul's Mystical Defense: Fire Absorption      +5% Fire Absorption      +2 MRR
Nystul's Mystical Defense: Electric Absorption      +5% Electrical Absorption      +2 MRR
Nystul's Mystical Defense: Cold Absorption      +5% Cold Absorption      +2 MRR
Nystul's Mystical Defense: Acid Absorption      +5% Acid Absorption      +2 MRR

Spines of the Manticore
2 Pieces: +2 Damage

Spines of the Manticore/The Wreath of Flame  +10 Ranged Power
Spines of the Manticore: Ranged Power      +3 Ranged Power      +2 Ranged Power

Deadly Rain
2 Pieces: +5 Ranged Power

Deadly Rain: +1 Dexterity      +2 PRR
Deadly Rain: +3 Ranged Power      +2 Ranged Power

That makes sense if you only action boost a few times per quest. Deadly Rain is on my main item because I run with 100% action boost uptime. Nystul's is the swap for situations with unavoidable energy damage spam that ignores evasion. (Horrid Wilting spam in Baba, the storm in RtSO, various BS in KT, etc. 90 MRR makes a big difference.)