EXACTLY!!!

The great thing that Alec Guiness did with the crazy old hermit was to give us so much detail in so little dialogue that we are free to read just about anything into it.

To Ben, Vader is Vader and Anakin is dead. So calling him Anakin wouldn't really make any sense. It would ruin ESB for new viewers. Plus at that point, Vader was just an evil character who had killed Anakin.

It always bothered me that Luke just called out to Leia like that. I just didn't think Jedi could call anyone. I guess they have a Force-enabled cell phone in their heads. Also, if Luke was able to do that-why didn't anyone realise any earlier that Leia had some kind of Force potential if any of the retconning is to be believed? Vader tortured her for quite a significant time and didn't get that memo?