I think they should be default while there is no crafting, to satisfy people who want them, but after crafting is introduced they should be a sight option along with other sights and attachments. But For now I think just making the sights more visible is absolutely the right call.
I can’t see Imperium to just ignore the fact that it’s soldiers can’t hit a thing in basically any low-light conditions. Like luminous sights are mostly extremely cheap when it comes to emissive radioactive paint, espicially counting the fact that radioactive materials involved in practically any production in imperium most likely. And i really can’s see how imperium wouldn’t put them on every lasgun. And as for gameplay I feel like they’re basically necessery to make something like lucius able to compete with Kantrael
Also I just checked and boltgun actually has slots for luminous dots as well as braced autogun. But those slots are empty which makes them allmost pointles. And then there’s infantry autoguns and headhunter autoguns which dont have them at all but their sights are at least rather good on their own with needle post. But then there’s recon las and Lucius with absolultely horrid sight pictures where luminous dots would actually make considerable difference imo