how the new psi type compares and shakes up psi builds.
Temporal Manipulation is very powerful, but it's almost completely a support school. So if your character is weak, adding TM won't necessarily suddenly make that character strong - it will help of course but what TM really does is help you use your other abilities more effectively.
Got a way to get good heavy hit in reliably? Entropic Recurrence will let you duplicate that hit, smearing the damage over time. Got a good attack you can use often? Psychotemporal Contraction (psi haste) will give you more AP and MP so you can position yourself well and use your good attacks more often. Limited Temporal Increment will reduce cooldowns, allowing you use those time-constrained abilities more frequently.
Basically, the new TM school requires a little bit of thinking about how to fit it into your build, but once you've figured out how best to use its abilities, it is probably worth the health pool hit for any build.