First off, I love putting a daemonblade in a unit of purifiers. Nice and ironic. =D
As for the list, couple of things.
-For the dreadnought, drop the missile, get another TL Auto. Same str with psy ammo, so no loss on vehicles, two more shots at twice the str of the frags which is probably what you'll end up getting against non-hordes.
-I don't like the idea of purifiers in a storm raven. If you want mobile firepower, go for interceptors with psybolt. Jump around dumping out s5 storm bolts like crazy, staying out of melee range or take a teleporter dreadknight with heavy incinerator and heavy psycannon, jumping around dropping templates, charging into vehicles if you need some anti-tank (6 str10 attacks, +2d6)
-For cheap HQs, i think a xenos inquisitor with a conversion beamer would work just as well. Gives you some high powered templates to drop for about 70 points.
Let me know what you think