Although I enjoy discipline healing more than holy healing right now (which is a matter of taste really, not because I feel like the one is better than the other) there will be some fights where I will try to see if holy works better. Usually a fight where I am not put to point heal and have to move around alot. Such a fight is Atramedes. The other day when we were wiping our asses off on Atramedes hc again, I decided to give holy a shot, since our holy priest was performing alot better than me (we can't have that, can we?). Unfortunately my holy spec was still a shield-focused build, inspired by a post by Oestrus regarding whether the changes made to shields would make shielding the go-to spell for holy as well. I wanted to try it out, and did so, but I didn't like it. But that's matters for another post! The point is that I had to respec and I did during a break. As always when I respec my holy tree I pause a moment when I come to Surge of Light vs Divine Touch. Our holy priest in the guild doesn't use SoL, and I am definitely no fan of it either. Even after the buff, I feel like the throughput gained by it just is... pathetic, to be honest. But I know there are priests who say that "this is a great life saver" and "I just love it when it procs, that's when you really need it". I must say priests must be of an especially optimistic breed, because I just don't feel this way about SoL. I don't want to spend 2 tp into something that might, maybe, be useful. Because most of the time it won't. Problem is that the alternative isn't all that good either, being Divine Touch. We have to put at least 1 tp either in SoL or in DT, so question is, which is more useful? 5% (10%) initial healing on Renew or 3% (6%) proc chance for SoL?
At first I decided to see how often SoL procs throughout a random raid. Since our holy priest doesn't use SoL, I had to check out random priests over at worldoflogs.com. At least that information will be completely unbiased from any ideas of mine. I chose fights randomly, both 10 man and 25 man, normal modes and heroic modes. The first thing I noticed, which came as a little suprise, was that most priest had decided to go for both Divine Touch and SoL. They're both pretty weak talents, but DT is based on Renew and SoL based on Heal (which is the spell we mainly use to proc this). I'm not sure where the benefit lies in talenting for both, since we really just take these to get further down the tree. Alot comes down to healing style, do you use Renew or Heal the most?
I've said it before and I will say it again - I am no theorycrafter, rather I like to experiment with numbers to get the general feel for something. This time is no different. Therefor, I settled for 10 numbers of SoL procs and 10 for DT healing (I can't spend all day sifting through wol-logs!). Although that sample is ridiculously small, it will give a hint on the usefulness of these talents. Even small samples will get us an idea, with which we can work on. The number of procs I found from these priests varied greatly, between 1 to 46, but we're still talking raids that took at least 1 hour, to a maximum of 6 hours (not accounting for possible breaks). I didn't check priests from russian/german/other countries of which I don't speak the language. Neither did I check if they had only one point in the talents or two. Like mentioned, the efficiency of SoL heavily relies on your need to throw alot of Heal/GH/BH throughout an encounter. Most holy priests will mainly heal with PoH, CoH, PoM (and Lightwell if your raid is good). SoL procs very rarely from spells that aren't used very much. DT too is based on a spell that most priests just don't use very much. It is time to find out which one of these talents that seems to be the weakest.
If I were to make a mean value of the times of procs I found, it'd be a rough number of course, but it still gives a general idea about the efficiency of SoL. Nevertheless I've found priests who've had it proc 46 times over 4 hours and 1 times over 6 hours, so the differences can be great. It is important to remember this.
The average raid for my SoL-sample took 207 min. During that time, depending alot on fight and healing style, SoL procced roughly 15 and a half times. We assume they were all used, and that they all fully healed (no overheals). My Flash Heal heals for about 17k (only own buffs), which gives 263.500 extra, free of cost healing (assuming none of the spells crit). Over 207 minutes that is 21 extra hps. These are crude numbers, so let's also take a look at maximum versus minimal efficiency in my sample too.
Maximum (of sample): 36 procs over 3 hours is ~56hps.
Minimum: 1 procs over 6 hours is 0,7 hps.
Even if my sample is far from statistically reliable, I feel safe in saying that at absolutely best, optimal conditions, spamming Heal/GH/BH, no SoL procs being overheals, we can expect to get 100hps from SoL. Even if this already is pretty low, even in an optimal situation, it is clear that SoL can be next to nothing in usefulness, depending on healing style.
Let's look at Divine Touch for comparison.
For the Divine Touch sample, the average raid took 252 minutes and DT healed for an average of 416900. Over 252 minutes that comes down to 27 hps. Here too the differences between biggest and smallest gain were pretty big.
Maximum: 1367000 healing over 4 hours is 95 hps.
Minimum: 17000 healing over 6 hours is 0,7 hps.
Looking at this it seems like DT has more potential than SoL, but the sample is too small to say anything definite. Overall the gains are small whichever talent you choose, and which one will be better for you will depend alot on, like mentioned, whether you rely more on Renew or Heal (and GH/BH). As boring as it sounds, both these talents are pretty much as useless as we feel like they are. DT will buff your cushion-healing somewhat and SoL will occasionally provide you with that extra Flash Heal, but none of them will make a huge difference. The best thing you can do is spec for either and do two raids to compare which seems to work best for you. Personally I will go with DT, because I feel like it will suit my healing style better, and also I feel like Renew is easier used in the content that I currently play over Heal/GH/BH, since there is alot of aoe healing and moving around. Like my holy priest guildie said it - the better gear we get, the less will we use Heal.
Oh and as a side note, I decided disc probably will work best for Atramedes anyway, just have to regear for shield spamming and see how that works. UPDATE: Yeah shield spamming worked, he's downed!