About the cards with Omen mechanic in Tarkir

Keyler

I've noticed that several of the cards with the Omen mechanic (2 side effects) in the Tarkir set have the same cost on both sides of the cards, many of them disproportionately expensive compared to the effect produced by their spell side. I don't know if this is intentional or if they forgot to change the costs on the spell side of these cards because the cards that do have different costs seem to be much better balanced.
For example, the Blue Dragon "Maran River Regent" requires 18 mana to discard a card and draw 3, very expensive for a Rare card.