That's okay. He strikes me as a player that'll settle down and get better with age and maturity. His prime will actually be 28-32 like back in the day.
By WAR Houston's current 3rd and 4th best batters are Brantley and Gurriel, both FA signed. Their starting catcher and RF are both FA signings. 3rd best starter is Miley who was a FA signing.
Just because you don't consider them "big names" doesn't mean they're not important pieces to the team. So there's 5 players on the Astros.
You know Stroman is going to want FA money after the 2020 season right? He's not going to give us a discount.
If we trade Stroman now we get a good prospect for him. We can still sign 2 starters instead of one. What's the difference if it's Stroman + FA starter vs 2 FA starters? It's gonna cost the same in the end, except the 2nd option we also end up with a controllable talent. We could even hypothetically bring back Stroman as a free agent.
Speaking of good buys Rick Porcello is available. If you can look past his era he's not so-so bad. And this will probably be his last year in Boston, which means he'll get out of that stadium, his away numbers are better than his home stats.