The triggered ability checks the power and toughness of a creature that enters the battlefield as it exists once it’s on the battlefield. For example, Triskelion has 1/1 printed on it, but it enters the battlefield with three +1/+1 counters on it, so it actually enters the battlefield as a 4/4 creature. Sword of the Meek’s ability wouldn’t trigger. Ditto for a Llanowar Elves that enters the battlefield while you control Gaea’s Anthem.

If a 1/1 creature that could not be equipped by Sword of the Meek enters the battlefield under your control, you may return Sword of the Meek to the battlefield when the ability resolves. The Sword will fail to become attached to the creature, but it will remain on the battlefield.

If multiple 1/1 creatures enter the battlefield at the same time, the Sword’s ability will trigger that many times. Only the first ability to resolve will return the Sword to the battlefield and attach it to a creature.