I've liked the idea of Gio on the Pirates for a while, and Grienke would certainly be an interesting gamble for where to spend a serous portion of the "available" cash. On the pitching front, I guess I actually lean most towards Miley, since he has some track record in the bullpen, and so in an ideal world, Keller comes up and displaces him. Between injuries and consistency, I don't think you can plan for that, which is why I don't think the Lyles/bullpenning idea is a very good one, even if it works out as well as it can. If you get Miley or someone else, Williams also has bullpen experience, so in the best case where Keller is blowing the door off the hinges, you can always just put the pitcher who is struggling most in the pen.
Put otherwise, if we go ahead with the depth we have now, I do think that the rotation shapes up to be very strong. This is an overly done cliche, because it's true in almost all cases, but if Lyles or some piggyback hybrid is starter #5, then we're one injury away from 2/5 of the starters being Brault/Kingham and Lyles.
I imagine most of the SS options would be for 1-2 years, with the situation being somewhat where Tucker could force the issue and relegate the SS to more of a utility or backup role. In most cases, that'd be fine. Marwin is sort of the exception, because he's probably not an everyday SS. I think Marwin might end up being a big gamble that goes wrong for whoever gets him, more than I thought at the beginning of the season, and I know this sounds absolutely bonkers, but I kind of like the idea of him being a bigger investment for offense, which then, along with Chisenhall, Frazier, and maybe a guy like Reyes, would give Hurdle some different tools to try and experiment with. There are plenty of senses in which what I'm about to say is complete horse shit, but I also think that kind of managing is Hurdle's strong suit. If he doesn't have his S-Rod on the bench to overuse, but rather multiple utility guys who each have different kinds of tools, it might be better than locking everyone down into an everyday position.
The more you swirl around the different options and kinds of depth, though, the more obvious the Machado idea seems on paper. We have the kind of supplementation via entry level contracts spread around throughout the roster, including -- and this is pretty significant, and different than history (although it's not as rosy if you are more skeptical about Williams, Musgrove, Archer) -- in the depth at starting pitching. Ok, we can talk in circles about Nutting's cheapness or other obvious reasons to doubt, but the path is pretty much right there to have a team that both has Machado and maintains a sub-100M payroll for the next 2-3 seasons at the very least.
Back to reality, the real issue I think is just where you are going to push for more. With Machado, the fit is basically perfect, because you can put him at SS. Pretty much everyone else, you have someone who can contribute positively. Marwin is maybe the only exception. The shitty thing is, even the right pick among the other needs just more firmly secures the mediocrity we've plateaued at.