So the two options JF & Natalya
JF does target more heroes than Natalya does. However JFs individual burn is smaller than Natalya… Equal to about 2.5 of JFs targets…
So basically JF does double the overall damage to Natalya. JF is also does it over 2 turns vs. 4 turns for Natalya.
Benefit of Natalya burn is that it’s undispellable while JF can potentially be dispelled (assuming they have a cleanser charged and ready to go.)
Comparing secondary effects:
Natalya has a single target mana slow. It’s quite large at -54% but it’s single target.
JF has both an ice defence buff AND grants immunity to defence related debuffs (& inverts them for four turns).
Natalya is Gen 1 HotM so has no elemental link or resistance
JF is Gen 3 HotM and has elemental link (+10% crit) and resists health stealing.
On defence JF is best as a flanker. He’s an okish tank but not really great there… Best position imo is left flank.
Natalya on the other hand is ONLY a winger… Not great in any other slot. Ideally she’s in the right wing to avoid her dot being ignored because a sniper also targets the same enemy…
JF is wizard class. Hotly contested by other heroes like Guin or Hel etc… Don’t know your options so can’t comment.
Natalya however is sorcerer class… A much less contested class. Again don’t know your roster so can’t comment more.
Natalya is a support hero. She’s good at targetting that one hero and doing some pretty hefty damage… But if you’re wanting a single target hefty damage, why not bring a sniper…?
JF on the other hand brings something unique… A fast speed DoT5 hero… Plus is a good counter to many heroes who appear on defence (e.g. Kunchen) because of the defence protection his special offers.
Against titans, I would again be taking JF over Natalya. JF has a higher attack stat & gives the crit buff which is very good in a red stack where tiles are the main damage inflicted (like titans).
If it were me, I would do JF over Natalya