If I ready my Ezreal legend, do I have to choose another 2 targets to use it again?

To answer your question: No, you do not need to choose two new targets to use Ezreal's legend ability again after readying him.

The Ruling

Ezreal's legend ability is an activated ability with a specific activation condition (a restriction on when you can use it).

• The Condition: "Use only if you've chosen enemy units and/or gear twice this turn with spells or unit abilities."
• The Activation: Once you have met this condition at any point during the turn, the ability becomes "unlocked" for the remainder of that turn.

Because the condition is a cumulative check of what has happened this turn ("if you've chosen... twice this turn"), it does not reset when you ready the legend. As long as you have already satisfied the requirement of choosing two targets earlier in the turn, you have met the condition for the rest of the turn. You may activate the ability again simply by paying the cost (exhausting Ezreal) whenever you have priority in an Open State.

Why this differs from Irelia

The confusion often stems from comparing Ezreal to legends like Irelia. As noted in RiftJudge FAQ #3291, Irelia's ability is a triggered ability that requires you to meet its specific trigger condition (targeting a unit) every time you want to use it.

Ezreal's ability, by contrast, is an activated ability with a "use only if" restriction. Once the "use only if" condition is satisfied, it remains satisfied for the duration of the turn, allowing you to activate the ability multiple times if you can ready him, without needing to perform the targeting actions again.

Summary of Sequence

1. Meeting the Condition: You play spells or use abilities that choose enemy units or gear as targets twice during your turn. The condition for Ezreal's ability is now met for the rest of the turn.
2. First Activation: You exhaust Ezreal to draw a card.
3. Readying: You use a game effect (e.g., a spell or legend ability) to ready Ezreal.
4. Second Activation: Because you already met the "chosen twice" condition earlier in the turn, you may immediately exhaust Ezreal again to draw another card, provided you are in an Open State.

Note: I could not fully verify this ruling against the retrieved rules.