I'm certainly wary of over-reacting to small nerfs here and there, but this isn't small. Only getting half the stated spell power bonus from enhancements and equipment amounts to about a 30% nerf, on average, versus where spell output should be.
Furthermore, when you also consider:
1. This comes at a time when enemies are dishing out MORE damage, and characters are adding even more HP.
2. High level arcane damage is getting a boost when used with even decent equipment (because older potency / element boosting items rarely went past levels 6 or 7)
3. This was put in at the last minute, after the last beta (I was on it, and heal and other spells hit for substantially more then). No explanation, no opportunity for feedback, and no notes about it in the release. I wonder why?
Turbine: This is really a deal-breaker. You can't expect people to invest time in characters, then continually yank the rug out from them like this. This isn't a nerf to a single weapon, or ability. It's a nerf to the divine classes, plain and simple. Neutering Freedom of Movement just adds to the head-shaking disappointment, but between that and destroying neutralize poison, it's just poor game design. You're saying "hey, remember those defenses you had before? Well, they're useless now. Not slightly worse -- useless.
I'm just fed up as a divine. There's a reason you test things like this in beta -- to get feedback. Sorcs screamed bloody murder at the original nerfing of metas, then they were adjusted due to feedback. But not this. This, you waited until the testing was done, then slipped it in.
This is just very disappointing. I have resisted conspiracy theory threads and the like in the past, but this truly diminishes my view of the development team.