There are some references to Holy Avenger vs Sanctified Wrath in the MoP All Specs thread, but both talents have since changed. Please point out any flaws in my math if you spot them.
Holy Avenger
Holy Avenger is (currently) akin to a 15 second Zealotry. Every HP generator produces 3 HP.
Sanctified Wrath increases AW to 30 seconds and permits more HoW usage.
Let's try to lowball normal play (to increase the value of HA) and say it takes an average of 5 GCD to generate 3 HP. So you get 1 TV every 6 GCD. HA would change 5-1 to 1-1. 17% TV usage to 50% TV usage - a tripling in TV. In 15 seconds (10 GCD) you would normally get 1.6 TV. In HA you'll get 5. Lose 3.4 HP generators and gain 3.4 TV.
Now, Sanctity of Battle should increase this as you reduce GCD on at least some of your attacks. Since this is napkin math I'm just going to be arbitrary and let's increase HA to a full 4 TV (this is possibly overvaluing - again trying to favour HA).
HA Bottom Line: Lose 4 HP generator and gain 4 TV.
Sanctified Wrath
Now to Sanctified Wrath. First we'll deal with the HoW increase. We'll assume every GCD is already going to be used (no empty GCD), so we're only gaining the difference between HoW and a lesser ability rather than an entirely free attack (lowballing SW a bit). We'll also pretend we're under 20% so HoW would already be available - simply gaining increase of frequency of HoW rather than adding it naturally.
30 seconds is 20 GCD. In 30 seconds you'd normally get 5 HoW, but SW lets us crank out 10. Lose 5 lesser-HP-generators and gain 5 HoW.
Now let's factor the extra 10 seconds of AW. That's 6.66 GCD, so round down to 6. Sequence of: Gen, Gen, Gen, TV, Gen, Gen. That's 5 generators and 1 TV that gains from AW that otherwise would not. 20% bonus damage times 5 Gen and 1 TV = 1 additional Gen and .2TV.
Combine the two. Lose 5 lesser-HP-generators, gain 5 HoW, gain 1 Generator and .2 TV. This means lose 4 generators and gain 5 HoW and .2TV.
SW Bottom Line: Lose 4 lesser-HP-generators and gain 5 HoW and .2TV. Above 20% this becomes lose 9 Gen and gain 10 HoW and .2TV.
Comparison
HA is lose 4 Gen, gain 4 TV.
SW is lose 4 Gen, gain 5 HoW and .2TV.
The Generator losses cancel out, and we can consolidate the TV, so we have:
HW gain 3.8 TV.
SW gain 5 HoW.
TV does: (((AP/14) * Weaponspeed) + Weapon damage) * 260%
HoW does: somewhere greater than 5300 * 161% SP
We'll pretend we have a nice slow 3.7 weapon speed. AP / 14 = 7.14% AP. Multiply by 3.7 = 26.4% AP. Multiply by 260% = 68.7% AP.
Sword of Light converts AP/2 into SP. So HoW goes from 161% SP to 80.5% AP.
Edit: Cannot subtract HoW's base damage from TV until we multiply each ability by its usage!
TV is 260% average weapon damage + 68.7% AP.
HoW is base damage + 80.5% AP.
TV is 260% average weapon damage.
HoW is base damage + 11.8% AP.
More napkin fudging - H Gurthalak damage is 6106 to 9160 - average 7633. HoW is average 5300. So end tier weapon is about 1.5 times HoW. N Ashkandi (first tier) was only about 90% HoW. So we'll say weapon damage will start about equal to HoW. For reference (used in a moment) high end first tier (PvP, actually) is looking like about 17000 average weapon damage.
TV is 260% weapon damage. 3.8 TV is 988% average weapon damage. 988% of 17000 = 167960.
HoW is 100% weapon damage and 11.8% AP. 5 HoW is 500% weapon damage 59% AP. 500% of 17000 = 85000.
TV is 167960 - 85000 = 82960.
HoW is 59% AP.
Reverse engineering we'd need (82960 / 59%) to break even. That's 140610 AP. Around 9 times larger than present values. Even with stat inflation, that's seems... improbable. Double to triple may be within reason, meaning we'd still be 1/3 to 1/6 the required value of AP.
Yes, above 20% SW would gain value, but nowhere near the 3-6 times greater it seems would be necessary. Again factor in how I tried to overvalue HA a bit (in hindsight a bad choice!) and undervalued SW, closer but still a great lead by HA.
Bottom Line
Sanctified Wrath looks really appealing and intuitively 'feels' strong, but in comparison to HA it may actually be lackluster.
Notes/warnings- I've worked on this off and on for 3+ hours with many distractions. Likelihood of math or logic errors higher than normal.
- This is napkin math.
- Guesstimates abound based on things like weapon and HoW base damage.
- This is on the current implementation - either/both Talents could change by the time you read this post.
- Corrected a bit of math noted above - this does NOT fully correct as the above numbers do not take into account the 2 min vs 3 min CD timers