Why? The base cost should reflect lower toughness but the awesome stuff should cost the same.
The current prices are good baselines, and there is no way an avenger with a 3+ and 4++ dodge would be anywhere near 12-13 points. Then you end up with a durable unit without much firepower thats too expensive (kinda sounds like a wave serpent

). When you fix the offensive you end up with super expensive t3 guys, and super expensive one wound models rarely work (and when they do they're like th & SS termies and every screams

at the sight of them.
I would rather see warlocks be listed as an upgrade in more unit entries then they are now (for example for DA, HB, etc.), and have the unit stay a retinue style choice. Mainly because our elite slot is already crammed full, and also because I'm a fan of the enhance style powers as well and its another way to give our units a bit of flexibility (which is needed to a degree).
I'm sure their price will go down in the next book, 4th tended to overcost elite style generalist units way too much, and people hated the ulthwe seer lists that ran the old warlocks with a ccw & sp, as cheap meat shields.