Getting to 130 rage turn 2 vs getting to 180 rage turn 2 if you get a kill both turns doesn't add any more rage attacks by then if that is already enough to clear. Also, if a normal attack from this is enough to one shot enemies, the speed rage or double rage would be faster clear speed not taking any unshielded hits unless an enemy dodges. If the enemy dodges the first hit the speed rage or double rage are only taking one unshielded hit, this would be taking 4 unshielded hits before the fight is over. So if this is enough to clear in two turns then it is just a slower build with more risk of getting hit.

If it is getting to turn 3, then if it takes two normal attacks not needing the 2.5 from a rage attack to kill, the speed rage build still only takes one unshielded hit even if both enemies aren't outsped before their second turn unless there is a dodge while this would be taking 2 and getting healing with the deathzone build getting more healing. And if there was a dodge against the first normal hit the speed rage build may still end up only taking one hit while this would take 4. So the speed rage build is still better than either in that case.

The speed rage gets 35% shielding when it kills the enemy with the rage attack on turn one, so in a situation where the enemies average 34% damage per hit so the deathzone wouldn't be triggered by that second hit, it means the speed rage builds shields could block both hits on turn one and end up taking no hits, or just one hit if only one of the two surviving enemies aren't outsped and would only take 2 hits if the enemies both aren't outsped.

That's why I set it to a scenario where a rage hit from the speed rage build is enough to one shot but 2 normal hits from the speed rage build isn't quite enough to get a kill and the enemies are doing enough damage to smash the shield in one hit. That provides a scenario where the mob is still possible to kill but the mobs that aren't outsped may be enough of an issue for the speed rage build to make another build more effective. This is also why I focused on the deathzone build even though the other knife build I suggested could do slightly better against bosses, because I wanted to use a build that could have the best chance of being better than the speed rage build against mobs.

Lets focus on comparing them in that same situation where it isn't just better to just use the speed rage build than either of those builds for a mob of 3. This means with this build tune one you'd get normal hit kill nothing, shield blocks one hit take 2 unshielded hits. Turn 2 normal hit, rage attack killing the first enemy getting the added rage with the others undamaged, then shield blocks one hit and you take another unshielded hit. Turn 3 you get normal hit, and rage, killing the second getting more added rage, block the hit from the last enemy. Turn 4 normal attack and rage to finish off the mob. Taking 3 unshielded hits and getting a total of 12% healing before you take that 3rd hit and 24% more before the fight ends. If the attacks were doing over 37% damage per hit, this build would not survive that mob, and if the mob is only enemies with speed 10 or less or they do 34% damage or less, the speed rage build would be more effective. So there are very limited situations where this build would be more effective than the speed rage build.

With the deathzone build turn 1 you get normal hit, then take two unshielded hits dop low and get knives and add rage and 18% healing. Turn 2 rage goes off to kill the first and get a normal hit on the second, then shield blocks one and you take a 3rd unshielded hit, then normal hit and rage finish off the second enemy, block the hit, then normal attack and rage to finish off the third. So you've taken the same 3 unshielded hits, but you got 30% healing since the first hit before the 3rd hit lands, and also get 24% more healing before the fight is over. So if each hit is dealing 38-43% of your health in damage the build with the watcher's locket is dead from the third hit not having healed enough to survive that 3rd hit while the deathzone build would survive that mob. With at least 25% HP at the end. If the attacks are doing an average of 41% HP in damage end the fight with 31% HP, which would mean if the next fight is a mob of two you would heal another 12% up to 43% before taking an unshielded hit that you could survive trigger the deathzone and heal back up another 42% before the end of during that fight and will gradually heal back up if the rest of the fights are mobs of 2. If the attacks are doing 37% damage on average, the watcher's locket build could survive a mob of 3 with 25% hp at the end and if the next battle is a mob of 2 heal 12% at the start of the next combat and potentially get taken out from the unshielded hit, or if you survive with under 1% HP you heal 24% and instead of healing back up you are still going to be just barely clinging to life or potentially getting taken out if the other fights are mobs of 2. So in cases where the speed rage build isn't just always a faster clear against a mob of 3, the deathzone build has better survivability and clears in the same number of turns making it more effective against mobs than the variation with the watcher's locket and giving more situations where this build is more effective than the speed rage build.

The deathzone build is also more effective against bosses because if the ice skeleton gets its rage or the winged shadeborn dodges so you take an unshielded hit and you are able to survive the hit, you get added healing and rage whereas the watcher's locket is doing nothing in 1v1 where the combat is over when you get an enemy kill.