As I was reflecting on Zen Mode yesterday, I realized that while Zen Mode Darmanitan was a failure, Game Freak took the lessons they learned from its failure and applied them to similar form-changing Pokemon in the future.
Aegislash swaps between forms much easier than Darmanitan, but it always starts in Shield form, so it can switch into attacks or tank a hit before attacking.
The most straight-forward adaptation of Zen Mode, as it's basically just "Zen Mode but also status immunity". Once again, first form is bulkier, which allows it to more easily set up Shell Smash.
A bit of a different spin on the idea, but you can think of Mimikyu as having twice as much health with a first form with exactly enough defenses to survive any attack on half (slightly below half in Gen 8). It's arbitrarily bulky.
Zygarde becomes bulkier when it gets below half similar to Zen Mode Darmanitan, but the form change never goes away, so it can heal with Leftovers or Rest and maintain its massive bulk. The base form (well, the 50% form anyway) is also very bulky in its own right, so it can easily get down to half health without getting KOed.
The second form is worse like with Zen Mode Darmanitan, but this time it's on purpose and the design leans into it.
A variation on Mimikyu, where it only has "arbitrary bulk" on the physical side, and can "heal" itself back up with Hail.
Really, the only time I think an in-battle form-changing Pokemon failed post gen-5 was ironically Galarian Darmanitan. For all the success they've had with form changers, they flubbed their attempt at redeeming Zen Mode. Though at least this time, it's more the fault of the alternative being absolutely nuts than anything fundamentally wrong with Zen Mode itself.
Aegislash swaps between forms much easier than Darmanitan, but it always starts in Shield form, so it can switch into attacks or tank a hit before attacking.
The most straight-forward adaptation of Zen Mode, as it's basically just "Zen Mode but also status immunity". Once again, first form is bulkier, which allows it to more easily set up Shell Smash.
A bit of a different spin on the idea, but you can think of Mimikyu as having twice as much health with a first form with exactly enough defenses to survive any attack on half (slightly below half in Gen 8). It's arbitrarily bulky.
Zygarde becomes bulkier when it gets below half similar to Zen Mode Darmanitan, but the form change never goes away, so it can heal with Leftovers or Rest and maintain its massive bulk. The base form (well, the 50% form anyway) is also very bulky in its own right, so it can easily get down to half health without getting KOed.
The second form is worse like with Zen Mode Darmanitan, but this time it's on purpose and the design leans into it.
A variation on Mimikyu, where it only has "arbitrary bulk" on the physical side, and can "heal" itself back up with Hail.
Really, the only time I think an in-battle form-changing Pokemon failed post gen-5 was ironically Galarian Darmanitan. For all the success they've had with form changers, they flubbed their attempt at redeeming Zen Mode. Though at least this time, it's more the fault of the alternative being absolutely nuts than anything fundamentally wrong with Zen Mode itself.
