The DPS output of Psi Melee has so much potential; GPB is a behemoth of an attack, maybe on par with one of the hardest hitting ST attack in the game. On top of that it can accept damage and hold procs, it recharges fairly quickly, and animates/activates smoothly (considering its damage). The fact that the set lets you throw in Concentrate and then add Insight on top of that, it really gives this power a best in class status.
Where I see the set coming up short is the predictability of its secondary set mechanic, Insight - while it can be predicted roughly as the OP has so graciously researched (THANK YOU!!!), the mechanic can definitely be refined. I've noticed anecdotally that Psi Blade is stacking Insight better(?) than Mental Strike - which has altered how I set up my attack chain (currently on my Stalker - BU, AS, GPB, PB and then an out-of-hide AS if anything is left standing). I'd love to throw in a Boggled (since it doesn't break Hide), but right now I don't need to. Level 54 DA Incarnate Bosses die from that one attack string.