We've already been through this problem with Guilliman.
Jacking the points on a single character doesn't scale to how much impact their buffs provide as games change in size. Either their buff become useless in a small game, or overpowering in a large one.
Initially GW tried to bump specific unit's costs, but that made those units unplayable for Chapters that didn't have access to Guilliman (IE: Fire Raptors). Next GW tried jacking Guilliman's points, and to a lesser extent that worked, except it made it impossible to bring him in anything less than a 2K game.
As to your side note: I 100% believe that it will be changed in the same fashion as the Iron Stone was.
Isn't that good though? Why would Guilliman, a primarch, be involved in a scout patrol? It just doesn't make sense. He should only be usable in larger engagements. The same with Feirros. In order to even have him and make it some-what effective you needed to build an Iron Council around him which ends up making the list quite expensive if you are trying to build a competitive list. I agree with not letting his aura affect flyers. That is perfectly reasonable. But nerfing the Iron Stone was not needed. Hell the Eldar have that same effect on every single one of their Wave Serpents. I don't remember anyone freaking out about that. It was good but it wasn't game breaking. It trapped all those units together making them easy to assault and tie down. It also created a sort of death ball that could be some-what avoided using terrain and faster units/vehicles.
So I just don't agree with most the arguments stating that it needed to be nerfed. "Easy to play" & "Point and click" is not a reason to nerf things. Everyone enjoys different play-styles. I remember people being salty for years about the old T'au lists with triple riptides. But people played around them. The meta shifted and changed. It just doesn't make any sense from a competitive stand point to have this knee jerk reaction. Give the meta time to adjust. It will adjust and things you think are op might not be as bad as you thought. It was certainly strong and there are certain aspects of Iron Hands that are still really good. But I guess I'm just more against the instant outrage and rioting over it so fast and GW's reaction to it. Most of us still don't know what is in store for Xenos and Chaos or what crazy combos are going to come out of that. Also, Genestealer lists were still beating the IHs lists from what I recall. But I don't see any outrage against the Genestealer codex.
I think the main issue is that people were able to paint the black over all their minis so fast that you saw a flood of IHs players. Making the problem seem larger that it actually was. I really like defending my point so I appreciate the arguments. I hope that I am sounding calm, because I am. Also if I come across as insulting I do not mean it. Just having a discussion with people that enjoy the same game I enjoy.
The IronStone's aura on a trio of Executioners has significantly more impact on game balance than a Serpent Shield on a Wave Serpent. The damage output of a Wave Serpent is nothing compared to an Executioner.
How do you balance an Executioner that is buffed with both the IronStone and Fierros' Aura? Do you increase its points cost? Does that work for the other Space Marine factions that lack the ability to grant their Executioners Invulnerable Saves and Damage reduction?
How about increasing Fierro's cost? Double it? Triple it? How does that impact his value in a 1000pt game? A 2000pt game?
Massive Aura sub-faction specific buffs like these don't balance at all well.