Depends on what their goal is. If they want it to be the primary spending card, help me get rid of my Chase cards (Saphire trifecta) and Amex Gold.

For me, It would be :

Current cardholder benefits plus
Alaska Lounge+ Membership
2 checked bags per pax on PNR (helps MVPs and non-elites)
First Class Companion Fare (I doubt we'll see this due to its cost, but can dream)
Higher earning rate for food and groceries (they compete with 4x rate with Amex Gold and 3x rate with Chase products here)
Higher earning rate for everything else (they compete with Chase Freedom Unlimited 1.5x (which = 2.25% when paired with Sapphire Reserve), and Chase Freedom Flex 5x bonus categories (which = 7.5% when paired with Sapphire Reserve)
Primary Insurance on Car Rentals
Trip Cancellation/Interruption Insurance that isn't limited to airfare-only.
Baggage Delay Insurance
Annual fee that doesn't exceed current Lounge+ price + Alaska Visa annual fee
Wifi or wifi passes (I don't think they can afford to do unlimited, even tho it would be nice)

They could also throw in low cost items like higher boarding priority than Alaska visa cardholders.