izigame.me

I normally love Paradox DLCs, despite their frequent critiques. I generally find that they expand the available mechanical and thematic space in each game by noticeable degrees. I think Fate of Iberia could be in that same category, and I would be able to recommend it without reservation. However, it has some serious flaws, and they will need to be addressed before I can recommend purchasing this DLC or playing with its functionality turned on while in-game.

DLC Integration

This is by far the biggest issue with this DLC so far -- it is very poorly integrated with the other two major pieces of DLC, Royal Court and Tours and Tournaments. While the latter is more understandable, since it came out much later and would hardly have been a gleam in the designer's eyes when they were creating Fate of Iberia, Royal Court came out in the same DLC season as FoA and its mediocre integration is pretty inexcusable.
Much of the meat of Fate of Iberia is handling the Struggle Phases mechanic, and pushing the Struggle towards Hostility or Conciliation by triggering point-calculating events. Many of the Confrontation triggers are still pretty well-tracked, since most of them are violence, but the Conciliation triggers -- which are mostly focused on building culture acceptance between Involved cultures, and respecting Involved faiths -- aren't tracked when they come from DLC sources. Many events triggered by Royal Court that build or degrade cultural acceptance are ignored, and with the release of Tours and Tournaments some of the main methods of building cultural acceptance (namely Tours) are completely ignored by the Struggle mechanic.
That the Struggle Phases don't really impact the available mechanics of RC and T&T is also disappointing, if understandable -- but these pieces of DLC really heavily influence the player's mechanical interactions with the game, and since their new mechanics (the court itself and all the new activities in T&T) are unaffected by the Struggle, it just feels like FoA has become a side note even while you're a ruler in Iberia.
This is my major complaint, and if it were fixed, I would be able to recommend the DLC.

Mechanical Impact

The other aspect of FoA that just isn't good enough is the way that the Struggle affects gameplay. There are some statistical modifiers, but it is still easy to forget that the country is at war with itself. It very much feels like the designers wanted to have Iberia be absolute chaos unless you put concerted effort into taming it -- not just the rulers, but also the average people of the region. You'll notice, reading through other reviews, that people are upset that just conquering the whole region doesn't end the struggle -- clearly, they think to themselves, the map is all one color now. Battle complete. Victory achieved.
I got the strong sense from the designers that they intended to have the chaos bubble back up, destabilizing situations that, in other regions, would be stable. For example, you can't form the Empire of Hispania without violently crushing the other cultures of the region first, converting 75% of provinces and pushing the Struggle into the Hostility phase. You're not fighting the other rulers of Iberia. You're fighting the whole region.
Except you're not really. There aren't many mechanical ways that the country fights you, just some fairly punishing requirements for bringing the struggle to an end without any fancy new mechanics for making that easier or less onerous. I would come up with suggestions on how to fix it, but generally my thoughts are these: I think it should be nearly impossible to form -- or maintain -- a single united polity in this region unless you are genuinely committed to the Hostility resolution and are near to being able to match its requirements. The factors that can break up and crumble united kingdoms should happen significantly more frequently, in ways heavily affected by the Struggle phase.
But that's hard to do, especially now that the DLC is out. I do not expect this to be changed.

Conclusion

Overall, I like the unique challenges and approaches of this DLC, even if I think they fall short of their potential. If it were better integrated with a fresh round of updates, I would be able to recommend purchasing it. Until then, though, it will be a lackluster addition to CK3, and I would recommend avoiding it, and even disabling it if its restrictions chafe.