I think workers should act like great people and be able to stack under normal units so you can build improvements and roads with no issues. Other than that I love teh no stacking now it makes it much more tactical
lol have you played the game? What you described is exactly how it works...
Every tile can have 1 Civilian unit and 1 Military unit on it.
Workers and Great People are Civilian units.
Spearmen and Infantry are Military units.
Therefore you can build Roads and Forts underneath military units.
And as for further up, it seems some people don't know that you can actually swap units with one another.
Seems a lot of people haven't actually played the game... They are crying and screaming for features that actually are in the game.
Why don't you guys try out a few things and get a good idea of how the game works before you bash it... 1UPT may be a little clunky, but I find it works pretty well. With a little practice, I found that I was able to move my troops around with relative freedom. It just takes some practice and understanding of some subtleties.
And as for your Mech Inf being killed by Crossbowmen...
What kind of position are you assaulting? You should be able to kill one and run away the next turn no problem... you have 4 movement. He also probably had amazing promotions (hint... they build up nicely on ranged units). You probably attacked through his Zone of Control, into an area where you were generally surrounded with overwhelming numbers (AKA a trap). It is completely understandable that you could have lost a single Mech Inf that walked right into his trap.