Yisrael Kleinhendler has a very interesting article on the "silk-screen sefer Torah" in Hakirah (vol. 19, Summer 2015). He writes (p. 219) about some of the issues halachic authorities had regarding writing a sefer Torah with a printing press. Some of them seem to apply to a “classicly” printed Sefer Torah as well
The Maharashdam was concerned that the ksav didn’t come out nice, regular paper was used, it wasn’t written lishmah, and it was done with chakikah (etching)
R Moshe Provinsalo was concerned that even if printing Sifrei Torah was done without chakikah, since it is similar to chakikah, one should not print Sifrei Torah so as not to come to doing chakikah.
The Teshuvah Me’ahavah was concerned with the upside-down letters and the common occurrence of having to discard invalid pages due to the many errors that were made in the process.
It is possible one could work its way around these issues, by using klaf, ensuring beautiful ksav, writing lishmah and maybe putting any erroneous page in geniza. As the article demonstrates, however, even with superior technology (silk-screen), there is very significant resistance to changing the age-old way of writing sifrei Torah by hand, sometimes for halachic reasons (for which there are work-arounds), most often for cultural and non-halachic reasons.
See the full article for more - it is very worthwhile reading in its entirety if you are interested in using "technology" to write sifrei Torah. See also (bottom of p. 210) the 11 rabbis permitting the "printing press sefer Torah".
Finally, some of the issues on this list might also be relevant here.