@Shadaoe
No, sado did miss that point but then if it will be possible to add trees/corn then this would be doable
No he didn't because sado is actually aware of the future additions to dynamic scripting (objects), while you obviously aren't (which isn't wrong at all, except that once you're explained these said additions, can you stop saying "he missed the point", admit you're wrong, and move on ?)
Please don't be in a "everyone else is wrong" mind, let's just discuss. Yes sometimes in a debate one can admit he's wrong, otherwise it goes into a vicious circle.
To add life to the city while pre-grown corn is cut you could even add one or two resources to other buildings so they start right away while the serfs launch the unstoppable ware machine, but that's optional as it wouldn't add that much.
About other points :
your people will get hungry around the same time, if you happen to have only one inn this won't be pretty.
The solution is simple, build more than one inn, or randomize the hunger of villagers in the script. Building more than one inn in a gamemode where you start with a heavy number of citizens is common sense (like not running out of stone before building quarries, sometimes it happens but usualy you're aware of it).
Once the players are used to it this isn't that much of a problem in my opinion, just a matter of time to get used to it.
About the amount of serf/laborers, either you add a fixed amount based on the maximum buildings you can do during the allowed time, or you magically add serfs and laborers every x buildings with dynamic scripting which in the end, is pretty much the same except the second one seems more natural. An optimal amount of serf/building can be calculated and if the player wants more then, he has schools.
And what about workers - I don't mean just serfs and labourers but also wood cutters, carpenters, etc., do you want to train them ? (seams fun..)
Dynamic script magic (like finishing buildings in a blink, which is the base of this idea), you add the woodcutter at the same time you build his hut and the player doesn't have to train the workers, which is much funnier indeed, and easy to fix
what about other issues ("it will be fine" it's not enough) ?
Most of your other points are only focused on game speed slider, which is not the topic.
I believe "it will be fine" indeed (although I never said that before.), because it's a 'fast mode' which keeps the spirit of KaM (after this prebuild phase), and dynamic scripts are expanding in a way that'll allow it to be fully done (and it can be extensively started already).
I think this fast building phase would be really great if you don't have enough time to play a full KaM game, because the rest of the game can still be at *1 speed (allowing fights to be understandable) and you'll lose less time.