What is the enhancement in mind? How should it look and feel?

Most important heals would show the heals that saved someone from death. I am not developer so I don't know what would be most effective way of implementing it, but I will try to explain it in modeled schematic combat log:
@0:000 tank has 150 000 life (100%)
@0:020 tank gets a hit of 100 000 damage and has 50 000 hp left
@0:040 tank gets a heal of 35 000 from Druid and has 85 000 hp left
@0:042 tank gets a heal of 60 000 from Shaman and has 145 000 hp left

important part:
version a)
@0:045 tank gets a hit of 75 000 damage and has 70 000 hp left
now what recount does here is checks last 5 secs from the hit and sees that @0:020 tank had 50 000, so he credits druids 35 000 heal an "important" tag because 50 000tank health + 35 000heal > 75 000 received damage = this heal made a difference for tank survival.

version b)
@0:045 tank gets a hit of 90 000 damage and has 55 000 hp left
recount checks 5 sec back from damage and sees lowest tank health @0:020 is 50 000 hp, now he checks for heals that saved him:
50 000hp + 35 000 druid heal = 85 000 < 90 000 damage | not saving heal
50 000hp + 35 000 druid + 60 000 shaman = 145 000 > 90 000 damage = saving heals, but in fact if there was no druid heal in between, shamans heal would have still saved the tank, so only shamans heal gets the "important" tag in this scenario.

version c)
@0:045 tank gets a hit of 120 000 damage and has 25 000 hp left
recount checks 5 sec back from damage and sees lowest tank health @0:020 is 50 000 hp, now he checks for heals that saved him:
50 000hp + 35 000 druid heal = 85 000 < 120 000 damage | not saving heal
50 000hp + 35 000 druid + 60 000 shaman = 145 000 > 120 000 damage = saving heals, in this case both heals were required to save tank from 120 000 damage so both heals get "important" tag.

Now I have no idea how computing something like that would affect CPU or Memory, so if it would be somewhat above recounts standard this could be calculated only after combat.
In the result screen you would see (for version c):

saving heals count for last fight:
druid 1
shaman 1

saving heal amount for last fight:
druid 35 000 hp
shaman 60 000 hp

Please provide any additional information below.

When talking about heals there is often an argument of most healed vs most needed heals at the most important time so I thought it would be nice to see some resemblance of this in recount. This would be a really great addition to weight healers after encounter.