It sounds like the microtransactions will just speed up R&D and Outer Ops completion times.
I'm fine with this, just as long as Konami hasn't forced Kojipro to massively extend the regular completion times to absurd levels (or worse, Kojipro did this of their own accord).
Its been a while since I beat PW but iirc, it took anywhere from 1-3 missions for R&D to complete, and typically 1 or 2 missions for Outer Ops to wrap up. If someone wants their Silenced Tranquilizer Mosin Nagant RIGHT NOW, sure, they can pay for that.
Just as long as the regular timers aren't absurdly long, and MGO doesn't become a P2W shit-fest, I'm good with this