Brobespierre

That was exactly it, @Rigel Kent! The uncustomized animation and the customizable "psychic blast" animation both fire off with the rhythm I've been familiar with on this toon, and it's only the palm assault powers that have him stand there with his arm out for way too long. I'll update the main post. Good catch!

Good point on the server timing discrepancy, and thank you for linking that report as well! I agree with you that it would be really weird for this to have been a deliberate change, which means that your network issue theory has more explanatory power. I did play around with some other blasters and the "lag" seems exclusive to my psi/ toon so far.

It does show an activation time of 1 second. I just tried some crude testing by disabling enhancements and queuing up two attacks, starting with psionic dart, and gauging how long it would take for the second attack to fire by using the recharge timer underneath the power. It looks like psionic dart is taking about 1.5 seconds to cast based on that admittedly imprecise experiment I just ran.

Yesterday (2/18) I noticed that the animation for psionic dart in the psychic blast primary for blasters had increased by what subjectively feels like twice the length of the old animation. My main toon is a psy/energy blaster and I've played it enough that I'm confident that the animation has changed from what it was even a day before (2/17) since it's a power I use frequently. It also seems to be longer than almost any of the other powers in the psychic blast set, and no other powers feel any different. I don't have any hard data because I never measured the animation time before yesterday, but I am certain that it's changed since two days ago and it's not a change mentioned in the patch notes for 2/18. UPDATE: It looks like it's only the "palm assault" customization options for psionic dart that are locking in to the unusually long animation time. Maybe the other reports of issues with psychic blast are related to them all using that palm assault animation, which has somehow gotten tweaked? @Rigel Kent discovered this and mentioned it below and I confirmed that on my toon the non-palm assault customization options work as they did before 2/18.