I think the first half of the game was very strong, but it will vary massively on how you as a player approached it? I spent all my time as grace being stealthy and utilising the different ways to distract or lure zombies out of their normal routes. I only used the pistol when I made a mistake and found myself cornered, or the hypo injector on a couple of notable zombies that felt like they were on the most visited corridors/rooms.
So when it flipped to Leon I had a great experience tearing through the place and getting payback so to speak. Conversely I've seen people going all out in the grace section, killing everything they can, taking over as Leon and finding his portion to then be empty, disappointing and short.
I think it would have been really cool if we had a flip moment where you go through an area as Leon first and approach it how you like, for Grace to then deal with the consequences afterwards. Go conservative then there's more zombies for Grace to have to navigate through but maybe more supplies as well (maybe even shared prizes in like in the casino room). Go all out and you can clear the place, but potentially then make it nightmarish for Grace on the risk that the zombies mutate and return back as those bloater head guys with few resources to deal with them. It could have been a really good self assessment moment of how you think about the rest of the game going forward and how your choices might come back to affect you.
They went with the full on action though, which is fine and quite enjoyable in the end (albeit way too easy), but it really felt like it split the whole thing into two separate games. So yeah I feel like that's an angle they could maybe explore in the future if they do something like this again, action sure, but not free of consequence.