I'm glad they understand where they went wrong for some parts of the game. If they do get to make a sequel, I'd honestly be very surprised if they did much of any pandering, making the game easier or less Metroid-esque.
Anyways, there's a couple of things I would effin love to see in a sequel:
I remember them mentioning something about a Roaming Horde feature back around E3 (I think it was E3, might've been later).
Basically at random times there would be a huge amount of zombies in certain areas and you'd have to use your CCTV cameras to plan out certain routes to avoid them, or simply avoid going to that area all together before they move on.
I think this could've added so much to the game, because outside of main missions, most areas are pretty devoid of zombies.
More large buildings to explore. Buckingham Palace is my favourite area of the game, without a doubt. It was huge, creepy and had plenty of little secrets and alternate routes. More of that please!
I would've liked a bigger hub area. The safe house and sub-way hub wasn't as big as I was hoping. (I'm used to Metroid hub areas being huge). Some random attacks on the safehouse would be cool cos I liked that section early in the game.
And finally, one thing I saw people complain about was the lack of attachment to their survivors. It would be hard to do, but maybe making some sort've random task for each survivor you play as could add a lot to you caring about them even more. Maybe one survivor is searching for a loved one,or their pet dog, or whatever. It doesn't have to be really in depth, but I think most people would agree that if they pulled it off, it would awesome!