I actually think we had way, way more of a plan this year than maybe even the last 2 years. Clearly we were going for 4-2-3-1 and clearly we went for 2 wingers straight away with Costa and Bernardeschi.
Benatia and Rugani were always brought in to replace a CB eventually, it just happened to be Bonucci. Personally, I prefer to let Rugani play as much as possible so a Bonucci replacement is not a big deal for me.
And we were never going to buy multiple CMs for this formation. It only requires 4 or 5 and we already had Pjanic, Marchisio, Khedira, (Bentancur emerged). So signing Matuidi is not exactly a Hernanes style panic signing. It's somewhat logical. Especially when he is a straight swap with Lemina/Rincon.
The only real glaring hole we've neglected is RB. But that hole is only huge because Alves went on a tear at the end of last season. But people forget we played without him for a good portion of last year.
We didn't even have a formation at the start of last season. We settled on 4-2-3-1 after a few months. Look at our bench attacking options last year: Cuadrado, Lemina, Sturaro and Kean....