3.2 has been active for a while and I've played quite a bit of it, so I can give my subjective view of what's going on in terms of holy itemization. Agree with it or not, but I've found that it works at a high level perspective (high level being Yogg+0, Algalon 25, etc).
The best types of items:
1. spellpower / haste / mp5
2. spellpower / haste / crit
3. spellpower / crit / mp5
Once you start really getting Coliseum gear with a ton of haste and reach the magical haste number of 675 (I actually have 672 right now and my FOL says 1 second cast) the number 3 itemized gear becomes better than number 1. At this point your flash of light is 1 second and your global cooldowns are 1 second, therefore flash of light receives no additional bonus from haste. If you've played any 3.2 you'll know that flash of light is used much more often. I even intersperse flash throughout Algalon when I can since a balls out HL spam is not sustainable anymore even with 32k unbuffed mana.
How much mp5 do you need? I try to keep it floating around 150 unbuffed. Any more than that seems unnecessary at this point, but it can only help. I personally prefer to max out my throughput before regen still just because the high level fights still require high throughput. Regen can come from a lot of places including seal/judgement of wisdom now.