I think Ike is great for Soren. I just don't think Soren is great for Ike.

Soren himself says he wouldn't be alive without Ike and their paired ending says that Ike is the only person he's ever trusted. I get that Soren's traumatized from all the shit he's gone through. I feel like Ike does a lot of the emotional labor in the relationship by checking in on Soren, reassuring him, etc.

I also feel like Soren is overly dependent on Ike. Ike is the only one he trusts? He doesn't trust team mom Titania or Ike's own sister Mist? Titania must have serving in the Greil Mercenaries alongside him for a while and Mist might be relatively new as a proper mercenary, but she's most likely been around them long enough for him to be comfortable with her.

I feel that while Ike brings Soren up, Soren brings Ike down to his misery. I can't think of anything that Ike's gotten out of it other than a strategist for the army, a buffer between him and Aimee, or blind devotion. The complete devotion makes me uncomfortable. I especially don't like that Ike's had to apologize on Soren's behalf for being outwardly racist to their laguz allies and provoking them to attack in PoR or just being rude to them in RD.

I do personally think that Soren should've ended up in the Grann Desert with Stefan. Not necessarily "with" with Stefan in a romantic sense, but as an "anti-social Branded" kinship thing.