To cover your points in reverse order:
In PvE, Shrouded Dance is going to be very useful, but disengagement from PvE was never really that hard. Most PCs can run away from NPC enemies by chugging an Invisibility potion. Shrouded Dance isn't that overpowered in PvE because NPCs largely exist to be beaten and the vast majority of them are lousy detectors anyway.
Will it be disruptive in PvP? In the sense of being a
disruptive innovation, it is already seriously redefining how people look at stealth strategies and balance. Before, stealthers had to take precautions and use strategy to disengage; or at least use potions. There was an element of a counter game. The Rogue uses Darkness to try and engage stealth? Well, that can be countered by Ultravision or True Seeing. Invisibility? Ditto, can be countered by potions. Corner-stealthing?That requires practice and an element of player skill. The point is, if one side didn't play well, they usually lost.
Shrouded Dance gives the Rogue the option to click a button to "win" if the other side doesn't have a detector, and it does so for an effective cost of 5 Performance.
The true low cost is part of the issue: people taking Shrouded Dance can ignore the Hide Pre-Requisite, because the PotM version is an upgrade of Stealth, not a separate effect. People who take Shrouded Dance don't think "I want to get Shrouded Dance but it will cost me 12 Hide and 5 Performance"; no, they think "I have 12 Hide already because I'm a Stealther; now if I spent just 5 more into Perform, I have one HIPS per day".
The other issue is that it the DC 30 check doesn't scale well with level at all. At level 9, this check is tough to pull off and makes the feat something of a Hail Mary. At level 20, with 23 Skill ranks and a DEX score of at least 18, most stealthers will already be just a meager +1 or +2 away from this being an automatic success (and therefore an automatic win against non-detectors).
So I would make two suggestion to balance this feat:
- The first is to raise the pre-requisites. Maybe bump the Performance requirement to 12 or 10 points. That would least give this powerful feat a serious investment cost.
- Make the check for it to activate based on a skill or ability other than Hide. Stealthers are going to max out Hide anyway, so a Hide requisite is effectively an open gate, and a Hide Skill check becomes an automatic success. Some stealthers can hit Hide skill checks of 90 or 100 at high level on this server; a DC 30 Hide check is merely a penalty on lower level characters.
I would therefore suggest making it a pure DEX check with a reasonable DC. It is much harder to max out your DEX score than it is to max out Hide, so at least with a reasonable DEX DC check, there would always be a risk of failure. Most DEX PCs will probably be sitting around on a +5 or +6 unbuffed, going up to maybe +10 or more when fully buffed.
IMO the DC should also be proportional to how much Performance the Feat costs -- if you're going to keep the low, low cost of Performance 5, the DC ought to be around ~18 . If you're going to boost the Performance prerequisite up to something like Performance 10 or 12, a DC check of ~16 is fairer.
That would at least mean that this feat always has has a reasonable chance of failure and success.