I think, that they will not do microtransactions. Why not: The target audience is simply not the target audience for micro transactions. I think micro transactions, and F2P works very well for a younger audience, while JA3 is most likely targeted at fans of the old JA-series (and let's be honest, we're not part of the younger audience anymore).
Also microtransactions for cosmetics work very well in multiplayer games, where you want to "show off", but it's rather uncommon in solo player games to pay for cosmetics. And if it's there, it's mostly a small add-on to support the developers, not the pay-to-win or annoying kind of micro-transactions from other games.
I still fear that they will f up things in other ways, but micro-transactions is probably not one of them.
