If the proposed trade is Romero + Kirilloff + Graterol for Realmuto, I'm definitely not making that trade.
It's really a decision between the following options:
-5 years of control of Romero
-top end, trending up prospects in Kirilloff and Graterol in the system and eventually 6 years of control (to join winning window later or be used as future trade pieces when Twins are contending for championship)
-Jason Castro as starting catcher in 2019
-Mitch Garver as backup in 2019 (or if really don't believe in his defense, sign a defensive-first back up)
-Realmuto for 2019 and 2020 (possibility for signing long-term but that is far from a guarantee and would likely be very expensive)
-Jason Castro as backup catcher in 2019
I think you can make a solid argument that option 1 benefits the Twins more than option 2 does.
I would. Especially considering that cost-controlled young starting pitching (Romero, maybe Graterol too) is arguably the most valuable resource in baseball right now.