Are you talking pve or pvp? Also are you specced into archangel or not?
You do realize that mind spike removes the dots on your target?

If you use mind spike you want to use it 3x in a row, as it will make your next mind blast and instant guaranteed crit. so a burst/finishing macro like
/castsequence (...) Mind Spike, Mind Spike, Mind Spike, Mind Blast, SW Death SW Death
/cast archangel
/trinket
/racial

In pve you want to dot as many targets up with Vampiric Touch & SW Pain, an keep Dev Plague up on main target (can only be applied to 1 at a time), use mind blast at 3 orbs and mind flay for the rest of it. The use of Mind Spike in PVE is very very situational,