I think Johnny also wants you to think over your choices, because of what he went through.
He even more or less implied how he felt/feels after he went through with the attack on the Arasaka. Grieving over the losses of his friends and beloved.
But, here is a far reached assumption:
You may think his attempts were futile and nothing changed, but he still is kind of like a symbol AND Yorinobu might have been very inspired by him. "When a Bomb turning the Arasaka Tower is not enough, oneself has to become the bomb" (or how it went). He wanted to change the Corp and/or bring Arasaka to its knees.
Also to the ones "defending" the Arasaka Ending as a good one, because "no one really died in the events". You then have to think about the consequences of a newly "born" Saburo Arasaka, who is the head figure (also an Engram, with possible personality change) and incorporates Arasaka, and is one of the reasons of oppressed people, poverty and expanding the gap in society. (while also doing some pointed good things as told by Takemura)
That was probably more in line with the original intent, keep in mind the Nomad ending was likely not planned at all. I think the entirety of the Panam questline was intended to be part of the Nomad lifepath questline that went beyond the prologue.
There are 4 endings to the game but only 3 of them have an official name within the game DB and the files.
- Araska is called Heir
- Rogue is called Legend
- And the solo (johnny's secret) ending is called Reborn


