Personally, I don't think Holland will be good this year... They released Broxton around this time last year with very similar/better numbers. I'm not saying they'll release Holland, but he just looks finished.
Wainwright out of the pen is an idea that Cards fans have kicked around for a few years now, but like Holland he seems done. He has no fastball, I don't want Wainwright coming in throwing 88 for an inning... Not when they have other better options in the pen.
As far as having too many SPs, they do have a ton.
Guys that aren't names non-Cards fans probably know like
Dakota Hudson, 1st rounder, 17-7 2.79 ERA
Ryan Helsley, 5th rounder, 26-8, 2.48 ERA
Austin Gomber, 4th rounder, 36-23, 2.99 ERA
Jordan Hicks was a starter in the minor leagues as well...
So you have those guys who IDK their potential, but seemingly could be trade-bait or back-end guys.
Carlos, Wacha, Weaver, Flaherty, Reyes, Mikolas, Wainwright (), John Gant
The organization has a ton of pitching.
But like some have said, Machado most likely isn't going to stay in STL. So if the want someone not named Reyes/Flaherty/Weaver sure, otherwise I'd pass.
If Ozuna was 2017 Ozuna and Carpenter was 2015-16 Carpenter with this pitching I'd go all-in with Machado