You even consider about taking a +1600 instant heal vs 30% increased selfhealing when its most needed? u mad?Yeh, smart heals are definitely better, especially when there's raid wide damage going. I mean, I'm not advocating blanket renew, far from it, CoH/PoH/Divine Hymn are all better tools for dealing with whole raid damage spikes, possibly even HW:Sanc (I use it on feuds, don't use it on crackles, I find even with the dps pushing nef's health, you have enough time that you don't need the 'omg HPS' to make the Sanc mana cost worthwhile). In those situations, yeh, I can see that Blessed Res is probably a better talent to have.
However, examples of when I like to use renew are say on Cho'gall when we're running back to the main group after killing an add, it's nice to use after I've put CoH on CD just on the add tank and any dps who have taken a bit of damage while I run back, it's good mobile spot healing. Or if someone is slightly loud on atramedes, it's useful just to give them that little bit extra healing while you aoe heal up the raid (or any other fight where someone is just a little lower hp than the group). After the reduction in mana cost especially, I find it a very usable spell.
I think it's very fight dependant as to which would be the better choice, I'll play around with using BR instead of DT, especially since we're only just moving into heroics (I enjoy stalling because the tank goes on holiday... sadface) and I can see it being very useful on Chimaeron and to a slightly lesser extent Halfus HC. Ideally you'd have 2 holy specs with these points swapped for different fights, but my offspec is my arena disc spec with different binds/ui and reconfiguring that several times a week for raids just isn't appealling (yeh, I'm not being 'the best I can be' for raiding, but it's a pretty minor difference and it improves my overall wow experience
But yeh, holy is a great spec, have fun learning to use it OP (and hopefully love it). While I think the shield cost nerf was badly designed and clumsy, I'm kinda glad they did it so I can play a spec that I find a lot more enjoyable without feeling like I'm harming my raid.