Hoping that includes significant AI improvements; from what I've read that's the biggest problem currently, and it's a major reason that I've stuck with III/IV, and non-Civ games. Only half of reviews being positive is abysmal, especially for a Civ game.
I am glad to see modding tools, but it's 4 months after release. Modding could address several of the other reasons I've been holding off, such as the art style, and maybe even the AI, but not having either modding or a halfway competent AI for 4 months boggles the mind. If the reviews had been great and I'd bought the game, I probably could have written modding tools for certain aspects of the game myself in 4 months, and almost surely with a few community helpers.
And while that may sound presumptuous, I have written a lot of modding tools for Civ III, so I have a better understanding than most of what would be involved. Getting something as polished as what I have for III wouldn't be possible without a lot of help in 4 months (at least with a day job; maybe if I worked at Firaxis), but targeted high-priority items likely would have been. In a way I'd have liked to have taken a stab at it to see how far I could have got before the official tools were released. However, Firaxis needed to at least have the base game in good shape at release to motivate me enough to try that.
Another civ is cool, but not really what is needed. Even my most-played Civ iterations hadn't seen me play 16+ civs in 4 months.
Overall, I'm anticipating AMD's new processors much more than Civ VI's next patch. Eventually I'm sure I'll pick it up, but Firaxis lost their chance to excite me about it in the fall, and the Endless Master Collection was on sale recently so I have plenty of strategy games to keep me occupied for awhile.