I don't think Iris needs one armor, but she should not generate so many points. Iris is usually worth between 21-25 points (21 if you had to use a 4 damage to kill her, e.g. 2x Enforcers; 25 if you placed her in a weathered & otherwise empty row). That's tremendous for a silver card. Compare (all these assume maximum value):
Jotunn: 15 power
Ida into Overdose: 15 power
Buffed Hattori resurrecting Toruviel: 20 power (this assumes Hattori was buffed to at least 6 strength).
Muzzle: 16 power (potentially more depending on how much it impacts the opponent's strategy).
Imlerith: 17 power
Caranthir: 8 power + 2 / turn + movement
Isengrim into Toruviel: 21 power
Ifrit: 13 power
Myrgtabrakke: 12 power
Stennis bringing out Trollolol: 19 power (14 immediate, 5 armor from Stennis's effect afterwards)
Notice one thing about this: Iris generates more points than all of these cards. Her point output is almost double that of Myrgtabrakke's for example. Further some of these cards are actually golds. A max value Iris easily punches above the weight of a comparable silver card.
There's only one redeeming factor for Iris and that is that she is not easy to use. The main weakness is on the turn she's played - the opponent can just pass immediately to force you to use one more card to pop Iris. This is mitigated by the fact there are combos that kill Iris on the same turn. Another important weakness is that she can potentially be weak if you can't trigger her / don't have 5 units on the board. However the first scenario happens only if one's deck malfunctions; it's rare that Iris will not die if one's deck is built to support her. The second scenario is more common but still not that big. Triggering Iris on 4 units is ~17 power, which is still easily competitive with the above cards. Finally Iris can backfire if the opponent has a lock and one does not have an unlock, so she is in some sense medium-risk high-reward, but the magnitude of the reward is big, and opponent cannot unlock her if she dies instantly anyway.
tl; dr: I think Iris needs a nerf to her points output, or at least some kind of "this unit is invulnerable until the end of the opponent's next turn" mechanic. I prefer the former, since the latter adds variance (do you have a counter? If so you win, if not I win). Something like boost up to five allies by four points. Iris would still be worth slightly more than all these other cards, but wouldn't be worth much more than them, and she would still be balanced by the fact she's harder to use.