According to MLB Farm, 57% of the balls he put in play were grounders. They were slightly more to his pull side and most of his base hits were of the opposite-field variety.
You're right, every player in the league can effectively hit 25-30 HR if they are just coached right.
KATOH has Tucker 4, Whitley 25, and Alvarez 31. KATOH is a computer model so it only knows the stat line. I suspect Whitley is being hammered for innings and not starting some games. https://www.fangraphs.com/blogs/2018-top-100-katoh-prospects/ Updated Summary Whitley BA 10 Fangraphs 8 BP 10 MLB 9 KATOH 25 Law 8 Tucker BA 15 Fangraphs 10 BP 20 MLB 17 KATOH 4 Law 21 Alvarez BA 62 Fangraphs 44 BP unranked MLB unranked KATOH 31 Law 40 Bukauskas BA 76 Fangraphs unranked with honorable mention BP unranked MLB 76 KATOH unranked Law 74
If Straw could hit more line drives than grounders (which is aa learnable skill), his slugging percentage should go up.
He already hits more line drives than anyone in the majors. He may be able to trade some grounders for more productive flies/fliners, but I don't think he can hit more line drives than he already is hitting.
Fangraphs released their rankings for recently graduated prospects with grades. This lets us see how graduated prospects might stack up as trade chips. They had Martes as a grade 55, meaning he is valued like a Top 50 prospect, ranked in the 24-42 range. They had Fisher and Paulino as grade 50, which would put them in the 43 to ~125 range. I pretty much agree with that and it backs up my thinking that a package of those 3 guys would be good enough to nab a star player like Archer or Realmuto.
If the Astros wanted to do that, it would likely get Realmuto. Archer would likely need more. For Realmuto, Astros would likely need a lot of other things lined up as move would cost the Astros their LF and two up and down arms that still have options. Realmuto's value to the Astros is more for 2019 and 2010 as McCann still is likely a starting quality catcher.
Yeah trading Fisher would require adding an OF from somewhere, but there are plenty left on the market. I’m not worried about Martes and Paulino, as McHugh, Peacock, Armenteros, Whitley, and many others provide plenty of pitching depth in the upper levels.
If Martes is good enough to acquire Realmuto with Fisher, he should be viewed as tough to replace. Paulino, not so much. There is absolutely no reason the Dayan Diazes and Janikowskis should be pitching this year for the Astros. While the Astros have a fantastic set of starters 6-~10 relative to the rest of the league, it drops off fast after that. Martes isn't being traded unless an arm is coming back.
a 6-9 of McHugh, Peacock, Armenteros, and Rodgers will be just fine, and you can likely add Whitley as the 10th starting in July. Then you’ve got the Diaz types like Hauschild, Thornton, etc. but frankly I’m not worried one iota about having a Diaz type as the 10th or 11th guy, given he will likely not be used or used in less than 3 starts. All this assumes no prospect like Cionel Perez, Hector Perez, Akeem Bostick, Yoanys Quiala, Dean Deetz, or anyone else breaks out in the meantime. Diaz made 1 start for Houston last season.
Not everyone, but the ones who have a plus hit tool, good plate discipline and motivation have an excellent chance to develop 50-55 grade power or better. Nor does he look like a 90 lb weakling to me.