Are there any technical reasons that have killed or will kill the DVI format as an output for TeX engines?
I know that the microtype package works better with pdflatex, but is there any technical reason for microtype not supporting DVI better?
Perhaps the main practical reason for not using DVI is that pictures and fonts reside outside the DVI file and so you need to distribute a package instead of a single document. Moreover, DVI viewers must then support the display of external pictures.
PDF of course bundles everything together, which is practical in that sense, but not practical if you want to extract the pictures etc. One could define a DVI bundle format (using zip for instance), but there is no interest and PDF is ubiquitous.