As long as Balon was Lord, I don't think the Ironborn would ever 'ally' with the Starks or anyone. At best they would simply attack the Lannisters as an opportunistic move whilst the main Western forces are otherwise occupied. Even in the case of a Stark & Ironborn victory, they would both be independent realms.
And if Balon perishes?
I can't see them being allied unless you married Theon to Sansa/Arya or Asha to Rob. All of those things you can do with the existing system.
How? Do you mean by "existing system" - "console cheating"?
There is an option to ally with Starks. You get a message when Theon comes where you get to choose whether to ally with them or "pay the iron price" and declare war on them.
It is not an alliance; it is a declaration of war on the Westerlands - while
at the same time, quite nonsensically, not against The Iron Throne itself.
It seems that Tywin's pretty much OK with the Ironborn ravaging across his homeland with the Tyrells too outside...and that Tywin can even easily meet his doom.
There is no alliance because the Starks are after the end of the invasion of the Lannisters still at their war. And while the Lannisters may have been kicked out, there is no way to help them either. And the buggyness of The Great War System leads to this effectively only
getting the Ironborn out of the war, since
all of my new Westland vassals continue their participation in a war against the Starks. While I think someone mentioned save-reloading should fix that problem, it didn't work for me in the end. And eventually, the Lannisters just rebel against my rule and rise up and they can still mount a potent force, just when I've returned all of my men home...so the only viable strategy for the Lannisters, as someone had already suggested, would be to lead
a long war of gradual total conquest, in which my aim would be to exterminate as much of the Lannisters and their prominent vassal families. While rampant murder might be canonical, I don't think that a long war of attrition is the way of the Ironborn. As the matter of fact, I am quite sure that their primary strategy is a swift strike tactic. That is also not a good path game-wise, due to the fact that by the time I
slowly siege through every darn little holding and go on to kill as many Lannisters as I can the Starks have already been beaten and my contribution to the struggle for independence is not sufficient. And by then the great wars across Westeros are already over and I'm actually alone against everyone.
I'm not sure what are precisely the events that led to that, but in one of my playthroughs
the Starks (Stannis as their liege),
my supposed allies, are actually the ones who were the most responsible for my defeat (they bent the knee).
We offer non-canon options in some places if they could have been canon eg: Aegon going East, it could have easily happened but didn't
And no for the last time we keep telling you we are not planning on any major ironborn improvements... we have told you this so very many times man!
I'm not referring to
major improvements; just tweaks. I'm thinking about the comment on Citedal in which a user mentioned that since the latest several patches The Iron Islands require a major workover; I thought the one who post had actually been one of the devs.
Having said that, some of the issues I've mentioned indeed do require fixing prior playing th Ironborn.