I'd much rather have Wheeler for the next 3 seasons. You have to keep in mind that Wheeler was a late bloomer (his breakout year was 2011-12, age 25), and his best seasons have been 2015-17. You have to factor in the intangibles. Not only is Wheeler a more important piece of the Jets right now, but it's well known in NHL circles that Wheeler is one of the leaders in the locker room, if not the leader.
Drawing a historical parallel, it would be like trading Iginla in 2006. Iginla was the heart and soul of the Flames from the beginning of the millennium until he departed for Pittsburgh in 2013. What have the Flames done since? In six years, they have had one good playoff series against a relatively weak Canucks team, and been blown out twice against the ducks, and missed the playoffs in 4 other seasons. Ignila was finally dealt to Pittsburgh when he was just shy of his 36th birthday.
I have a feeling Wheeler will be more in line with St.Louis, Selanne, and Jagr. He will continue to be a top player until his late 30's. By that time his contract with the Jets will be winding down, if the choose to sign him. It also sends a negative message if the Jets don't pursure Wheeler, who seems to love playing for the Jets. It's not like we are a top destination for UFA's.
Ehlers has the ability to be over a PPG player, but I cannot see him ever becoming a leader for the Jets. Maybe in 3-4 years, Ehlers will eclipse Wheeler in terms of how important he is to the Jets, but that would cover most of any hypothetical contract he is offered by the Jets. It seems as though the people who want to trade or let go of Wheeler, can't see past his age. There have been too many examples in the history of the NHL to disprove the theory that after 30, it's all downhill for a player's career.