Melee Splash or Elemental Proliferation?

Ok, so long story short. I'm making an Oro's Sacrifice melee build. I planned on Melee Splash being my AoE support. However, a good friend of mine said I should rather use Elemental Proliferation. He said he doesn't know the math behind it, but burning damage works amazing. And now I'd like to know why's that so... can someone explain me the formulas on this example?
I've got this Oro's Sacrifice:

My dmg multipliers off nodes:
- 147% incr. fire dmg;
- 30% incr. fire dmg. with weapons;
- 54% incr. elemental dmg;
- 40% incr. elemental dmg. with weapons;
- 80% incr. burning dmg.

Burning damage allows you to double dip in a lot of circumstances. Any fire and elemental nodes you have will first increase the fire damage you deal and then if you ignite an enemy, they will apply a second time to increase the burning damage.

- 147% incr. fire dmg;
- 30% incr. fire dmg. with weapons;
- 54% incr. elemental dmg;
- 40% incr. elemental dmg. with weapons;

These multipliers will apply to the fire damage, increasing it to 371%. If you ignite an enemy, then the burning damage will be calculated based on the damage dealt.

- 147% incr. fire dmg;
- 54% incr. elemental dmg;
- 80% incr. burning dmg.

These multipliers will then apply to the burning damage. Base burning damage is 80% of the initial fire damage that caused the burn over four seconds. So, 80% of 371%. Now, apply the burning modifiers, which are +281% for a total of 381% burning damage. So, you deal 381% of 80% of 371% burning damage which is 1101%. This is dealt over four seconds though.

If you lower the enemy resistance with a curse, then the lowered fire resistance is also applied twice for calculating burning damage. Note however that this also holds true if an enemy is resistant against fire, a 50% resistance will first lower the initial fire damage with 50% and then lower the burning damage with 50% again. You can get by that by hitting another enemy who doesn't have fire resistance.

Since Crystalgate explained why ignite is so awesome, I will give my opinion on which support you should use.

Both

Chance to ignite is per target. Elemental Proliferation will make one ignite make everything ignite.

You win.

In all seriousness it's possible to one shot entire packs. That's the basis behind both burning discharger and detonate dead burning builds.

Cast flammability first to lower fire resistances to increase burning damage on the targets with the added bonus of increasing chance to ignite.

use fire trap too, i believe units on the fire trap area count as ignited

along with units being affected by [un]righteous fire and searing bond

BTW, will chance to ignite from Oro's and support gem stack? Ot I'll get an average as in crit + support?