Ok, firstly, I understand English isn't everybody's first language, but a spell checker at least would help, was pretty difficult to get through some of that.
Now, onto the points you made;
1. The manual craft is *supposed* to be more efficient. Just because you can make things a little faster by hand doesn't mean you should, think about this, if you have a production line of 4 different items being made at once, you couldn't make enough by hand to make the same amount in a minute that they all would together. If you need some resources and you need them now, then yea, use manual craft if you don't have them in storage, otherwise the production lines are your friend, they'll keep going even when you're building, exploring, having a cuppa, or whatever else.
2. The way to stop them crashing into each other is simple, keep the holographic markers up that shows the route of the other vehicle and then just make sure you don't intersect it when driving another one, just be 10 feet to the left/right of the first one.
3. Pretty sure that's a bug, haven't tried it myself, but I can test and get back to you.
4. There's an easy way around that, connect two rods and 1 plates to a merger then it's getting twice as many rods than plates, but if you're feeding into an assembler to make the plates, just connect the plates and rods directly to it, it has two inputs for a reason, it will then use the resources as it needs them.
5. Yes, this is a much asked for change, having a hand, body, legs and head slot.