Apart from tighter seating on I2, both are "full service" to the extent Iberia is a "full service" airline. I wouldn't bother classifying them that differently.

Although it does raise a good point. If you book and I2 with I2 directly as opposed to booking with IB directl you don't get luggage included: so perhaps IAG has seen that this approach may already have some value to them and are trying a spin on a similar aproach with BA at Gatwick (though without the benefit of the lower cost base I2 brings to Iberia).