[Darko]

Do you really need anything more than weapons capable of planetary destruction?

You also have to take into consideration that man has forsaken computers because they were enslaved by them, which is why there are 'mentats'. Humans conditioned to act out logical computation that computers were once used for. I think this might be why the technology seems a bit primitive, even as advanced as some of it may be because even our most advanced weapons are dependent on computer technology.

Now that I think about it, the Weirding modules in the movie might have been a cheap way to employ the lasguns. If they had used lasguns, it would have cost them a ton more in special effects.