The distinguishing criteria to differentiate blue "looting" and red "rumaging" is that blue draws first, then discards, while red discards first, then draws.

Since caring about instants/sorceries is not a distinction between blue and red this card reads as a blue card printed in the wrong color.

Suggestion: "As an additional cost to cast ~, discard two cards or discard an instant or sorcery card. Draw three cards."

Changed to suggestion, thanks for the advice SI.