Bhoy
Chieftain
You do know units can pass through other units as long as the tile on the other side is free, right? Also the whole point of a choke point is to limit movement, and yes it can get annoying, but what can I say, its a choke point! Also in you scenario a warrior/worker can share a tile, another unit can still pass through. It takes some managing, but it really isnt that big a deal, plus a worker takes a few turns to build a road/improvement then hes gone.
If it's a hill or a forest or something that hogs 1 turn then you can't pass through it while a unit of the same type is on it. I've had to do all sorts of manouvering to get units where I want them to go which distracts from the game play.
Anyway, another point:
Automated workers decide to swap continents whenever something needs done - they disappear for about 10 turns before popping up somewhere else to finish a mine. Not a huge issue until they start getting munched by enemies and barbarians while mid sea.