Between Ramsey, Wilshire, Perez, Giroud, Iwobi, Elneny, Cazorla, Walcott, and Ox, there are three available spots for a given matchday. This presumes any clear "A" squad includes Ozil, Alexis, and Xhaka.
That's sort of an insane amount of permutations. For the first time in awhile, there's a strong possibility that the best base lineup holds more of a 4-4-2 shape than 4-2-3-1, with Perez playing up top underneath Giroud. It's been observed that such balance has been beneficial for both strikers in the past, and the argument is that Perez is enough of a creator at the top of the box, that you don't lose much shifting Ozil into slightly more of a B2B role with only Xhaka behind him in central midfield.
Personally, I'd rather bench Giroud, play Perez as a pure striker ahead of Ozil/Alexis, and see what happens given extended time to build chemistry. In this path Cazorla, Elneny, and Ramsey are your clear B2B possible best options, and Ox, Iwobi, or Ramsey could all be the starting winger opposite Alexis. If everyone's on form, Ramsey and Cazorla's flexibility may make them more valuable as first-team substitutes.
A lot of Ramsey's role seems to depend on what Perez and Elneny show the boss. Wilshire and Walcott are 3rd-stringers whereever they look at this point. But given the narrowness of the competition, I'd expect it to be very hard to see a definitive first-team lineup or formation at all this season. It may be particularly matchup-specific this year, in addition to the usual fitness/form variables.