I've been playtesting Psi/Bio up to level 41 so far, and think I agree with you @Without_Pause, and will likely reroll to /Energy Aura.
Strangely enough, I feel the current set up has too many offensive abilities, making it easy for me to lose any idea of an attach chain. Yes, /Bio gives me some additional AoE damaging attacks, including a proc-bomb in DNA Siphon, but these attacks generally are not high damaging and seem to pull the ire of the mob on me more often then not. As you point out, with /Bio being less of a Defense set, that mob tends to chew me up.
I recalibrated my psi/energy build and changed out Speed of Sound for Vengeance and Psi Mastery with Soul Mastery. Gives me an extra defensive power in Shadow Meld, with only 9 seconds of downtime. Any thoughts anyone?