Changing coach will invariably see an upturn in results for at least a short period of time but the litmus test is what they do over a longer period of time.
I guess DDR and Calzona are now superior coaches to Allegri. I also know that anyone is better than Allegri. Danger for us is changing coach and then doing so every season like the meme club we are on the way to becoming, something like Napoli under ADL. Clubs like Napoli and Roma have intense pressure but it's mostly from localised fan bases, it's not the same as Juve. Could be that DDR and Calzona become great coaches, but it's not some tried and trusted method to change coach and all is great, that's bollocks.
Allegri isn't going to be here long term and I'm happy with that, but also have reservations on who replaces him, because I don't see guarantees from realistic options. Would be great if we could get someone young and/or associated with the club who becomes a revelation. And as I've said many times, how we play generally isn't important to me, results are far more weighty. One often comes with the other.