Due to the new update, I read on the wiki that the 'Walk it Off' achievement is impossible to get. To fix this, I have come up with a solution.
Make it obtainable by giving someone a Spark of Life and make its description say "Revive a fallen party member by giving them a Spark of Life". Or you can do it the other way and bring back the old revival system and work something out with the new one. Your choice, OOO.
What you just said would make more sense for an other achievement:
Helping Hand
Revive a downed party member.
Walk it Off would need something else.
Because there are 2 health sharing related achievements:
-Revive a teammate
-Revive a teammate when at 1 píp of health
Make Walk It Off to just revive yourself, like the title of the achievement already says.
The 'revive yourself' is already covered by 'Jump Start'... or did you mean using a SoL?
Sincerely, I don't know if I want 'Walk It Off' to be replaced... maybe create an equivalent at most.
I would say that the achievement could be reworked as "Revive a party member with a Spark of Life after they were downed from extreme damage.", and the "extreme damage" source could be from powerful enemies, such as Lumbers, Rocket Puppies (Or as I call the Tier 3 ones, 'Nuke Puppies'), Vanaduke's banhammer smash, or Alpha Wolver chomps.
However, I know the game itself has a built-in 'massive damage reduction' system when your health is low. You might have noticed this when fighting off a Lumber and you have only a small amount of health left, and it smashes you with damage that would've otherwise have killed you, but you somehow lived with just a fraction of your health remaining.
That would give a rather unique feeling to 'Walk It Off':
"Walk it off, soldier! We don't need you getting pounded to death by these guys!"
"I just got smashed into the ground by a Lumber... just HOW do you expect me to 'walk it off' after that?"
"Simple. *gives Spark of Life*"
*should probably be smacked for this*
Old players already have impossible-to-get items already. Groundbreaker set, honor blades.
Leaving the achievement as is wouldn't hurt anyways.
I remember reading a post about this around the time the system first came out. But i do like your idea about the spark, it's actually something i have been saying for a while. The old rev system is never coming back tho (even though i want it to).