The Mariners need, above all, a couple of OBP guys to hit in front of Cano, Cruz and Seager (which should be the 3-4-5 batting order if Cano can, ahem, overcome the I-can't-hit-batting-third syndrom that plagued him this year. If you look at those three's RBI totals they are shy of 95-110-90 RBI's as a direct result of the lack of top of the order OBP.
I LOVE seeing Marte at shortstop so far, and I'd hate to disrupt the immediately obvious chemistry with Cano. With Marte you get a sense of COMMAND of the position. Every move of his shouts, "I got this." (This by the way is a trait that Cano has in spades.) Taylor has the skills but not the command. Miller has the athleticism but not the skills and definitely not the command.
I get that Marte to CF looks to solve the CF problem, and that position scarcity makes this position hard to fill, but why move him off the position he already looks able to lock down? And if he indeed continues what he started late this season, he could be one of the two top of the order OBP guys. Taylor would be perfectly suitable as your bench SS. Then you prioritize a .330-.340 OBP CF'er. Honestly, if the M's can do whatever it takes to get that piece, and if Marte doesn't fall prey to Mariner-player-development-disease, they can make do at 1B and then they are left with what in the world to do at catcher (leaving pitching aside for the moment). They would have an offense. Two OBP guys in front of the Big Three amplifies the value of the Big Three. It's the classic force multiplier.
Miller in CF to me has the same problem as he has at SS, the needed athleticism, he can develop the skills, but my gut tells me he will never command the position. In fact, my gut tells me Miller should not be entrusted with an up-the-middle position for this very reason. Thus his value is more limited, because that makes him a corner OF'er.
Is sum, I get the logic behind the suggestions, but personally I believe the particulars in this case mitigate against them.