Hehe. I really hope this title lives up to expectations.
The longevity seems to be the biggest question, but im beginning to think that the modding ability could really help it. It might be that you play it for a while and try various things, and then run out of something new to do, a lack of direction when there arent objectives (wouldnt really count achievements as gameplay objectives the same as say 'keep citizens happy for 10yrs without using public transport', which can easily be set as an achievement, but i'd prefer it if you opted into that mode and it disabled stuff and you either 'win' or not, but anyway thats sandbox games and its not an issue.
What i think will keep people playing, maybe not for months straight, but certainly going back to it, will be mod collections and interesting items.
Yesterday the person at CO who's responsible for the modding side let slip some information, before removing it... but people spotted it and reposted it, and today he's been fairly open on questions about it. More technical stuff for the people who'd be creating new assets, rather than some of the easier stuff, such as expected poly counts.
They've said that if you're building a house, then to make sure the X-axis is offset within the model if you dont want it to be bang center in the plot. From there things like fences, hedges, plants, trees, mailboxes etc came up, and they'd suggested that they just build the house, because all the other stuff you can do within the CO-built tools. They even went on to confirm that people can even make those small assets too, so if someone wants to build a swing, a tree-house, swimming pool etc then they can make that (or get it from Workshop) and plop it all down and end up with the finished asset.
Someones already created the German style apartment block they live in. Looking forward to seeing more of them. Not entirely sure how the fits into the 4x4 limits, it'd be okay for a plopable (8x8 limit) but i suppose if need be they can chop it in half.