Many of the applications you quoted are still in Devel or Testing, so they HAVE to be unfinished, whether you like it or not.

About Prboom and VGBA: i managed to finish both Doom and Doom 2, many expansions of them, and a few GBA games at a pefectly playable speed. Many PC emulators can't do that, and many games will never work on a emulator without problems, so this is an amazing goal for those free and open-source applications on a tablet IMO.