1) It is not clear that you need pioneers to upgrade outposts. I figured it would use production from the nearest city at first, but then found out online that pioneers are used for the upgrade.
2) I don't understand how production is calculated, it seems like you can ramp up a city quickly from tiles to build things fast but still can never get below 2-3 turns to produce something.
3) This was discussed a while back and I think it would make sense to use at least some production to build improvements in addition to the logistics cost.
4) It would be 'nice to have' a production queue of just one other production item on a city. It doesn't seem like more than 1 additional item is really needed but there are cases that I know what the next thing I want to build in a city is.