Thanks for playing, and glad to hear you enjoy the concept!
Moving soldiers is something I haven't added yet, but it is planned for the next update. It is a bit tricky to balance since it could be used to save a tower from getting attacked. I think to work around this I will allow towers to move only in the same area they are placed, and when moved they will move to the new position slowly. I think this will also add another layer of engagement and strategy. Perhaps moving them more freely could become some kind of upgrade in the future like a heli pickup as well.
I am also adding a difficulty indicator to each wave which should hopefully help with suggesting when to back out of a mission, but I will have to see if it actually helps.