I'm talking about the VSE. Right now you have to waste 3 (3!) tracks in order to make a transition between two clips; the first two of the tracks you use for video strips and the third one is for a transition strip itself.
As far as I know, there is no addon that let you make transitions on the same track. If there is any, please let me know. I don't know is that even doable with python or you should code it in core components and compile afterwards.