As far as electron beam point heating, I don't see how it has to be less precise than laser heating. The process would have to take place in a vacuum chamber. As a benefit of working in a vacuum, metals that would react if heated in air could be used.
The problem is absorbing the electron beam. It takes a set amount of depth to absorb the energy and melt, so your layers at least are limited in how thin they can get.
I think that that's a problem to a greater or lesser degree with all the processes. The need to absorb energy in one fashion or other. These are exciting times for new tools.