Assuming I'm reading the Changelog correctly: If the new cap is actually 5, then full Pheromones is +2.5 on non-Blind targets. Which is most of them if you're not a Smuggler or have a Blind Chance weapon. Or Kineticist with Debris Field, I suppose.
Against Blind targets, it's +7.5.
Edit: Actual cap does seem to be 5.
2+2+2 = 5/10
Blind Chance is exclusive to Phaedra, by the way. (Grenade Launcher/Urtanium Gemstone for Custom Weapon.) Blind usually doesn't last very long, either.
As an aside, I never found Pheromone perks to be necessary. My characters that Tease the most don't even have any.