Stealth counterplay/synergy in other Classes
We all know that the Rogue Archetype will be largely defined by it's exclusive access to 'True Stealth' mecanics, likewise taking Rogue secondary archetype will likely give access to Stealth augments to splash some stealth into the builds, though likely in diluted form. Meanwhile Rangers have access to a distance dependent 'Camoflage' ability that looks to be a lesser form of stealth. It dose not currently known if Ranger secondary archetype will give any access to this Camoflage.
We also know that "countermeasures found in itemization, other archetype abilities and environmental that stop stealth." this is presumed to mean both Rogue and Rangers aka both Stealth and Camoflage can be defeated by a given countermeasure though not nessarily with equal ease. I won't address items or environmental effects as I wish to focus on archetype abilites.
The concept of synergy with sealth is topic I've never heard discussed before, I define it as any class ability wich comes from a non-stealthing character which could give aid to a stealthed team-mate to specifically gain or maintain their stealth, including ones self. The simplest form of synergy would be COUNTER-counter-stealth aka supressing the abilities which counter stealth.
For example a duff to stealth detetion call 'awareness' causes Camoflaged enemies to be revealed as if their distance to you is half of what it actually is, while a 'distracted' debuff causes them to be treated as if their distance is doubled. The exact mecanics of breaking the Rogues 'true' stealth is not clear yet clear or likely to be universal but the same half/double dynamic would be applied, be it to the duration/range/power of what ever abilties are used to counter it. As you can see by their nature they two effects cancel out and applying one is equivilent to a dispelling/counterspelling the other.
The first question we must answer is "What Archetypes have Strong Counter-stealth abilites, and which are weak or no such abilities?"
In my opinion the Answer should be
Strongest : Ranger
Strong : Mage, Bard
Weak : Summoner
None : Cleric, Tank, Rogue, Fighter
Second question "Which Archetypes should have synergy with stealth, which would have weak synergy and which would have none?"
Strongest : Tank
Strong : Bard, Fighter
Weak : Summoner, Cleric, Rogue, Mage
None : Ranger
Details on how I see each Archetype filling these roles.
Ranger : Only Rangers should have passive mid-range always on stealth countering abilities, though they can still be snuck up on it they are the hardest class to surprize, note this passive can't be buffed up to be any stronger then it already is because the Ranger is basically always on alert. They also have active detection abilities that can scan large areas at great range for stealthed targets without dealing damage.
Tank : As the nature of tanks is to draw Agro they have the greatest ability to place 'Distracted' debuffs onto enemies though Taunt mechanism which reach far and wide hitting all enemies and last for a long time. A Tank going into a taunt is thus the ideal time for Rogues/Rangers to conduct an ambush.
Mage : Only have access to short range active detection spells (Archane eye) and the implicit ability to drop AOE spells to 'smoke out' a stealthing target. Some status effects caused by elemental damage can produce stealthy synergy such as blinding and deafening, being on fire or frozen makes it hard to notice things.
Bard : As a support class Bards have strong abilites in both countering and synergizing with stealth, they can provide group wide stealth detection 'Alertness' buffing and maintain it nearly constantly which can make the group roughly on par with a Rangers passive stealth detection ability. Bards can also cause 'Distraction' debuffs to multiple enemies at short to mid range which can help make the difference for Rogues.
Fighter : The fighter is the single target and short range specialist in Distraction. Their damage delt in melee can inflict distraction, and they can do a long range single target 'Challenge' which is functionally a 1 person taunt.
Summoner : Atleast 1 summonable in their skill set would have stealth defeating properties, but sending it against the enemy would leave the Summoner himself exposed as they lack any organic detection. Likewise 1 summonable would have taunting functionality. Ranger or Tank secondary archetypes would shift all their summons to counter stealth or counter-counter-stealth respectivly.
Cleric : Minimal stealth synergy via Distraction debuff applied to targets they hit with Radiant damage. Clerics are one of the more vulnorable (and high priority) targets for Rogues.
Rogue : Possess a simple "Smoke Bomb" ability can create a short lived zone in which stealth is easier, this functions largely as an escape mechanism for them to re-aquire stealth to flee it but some offensive potential exist for two Rogues to assist each other.