somewhat random thought: I was once thinking about how it is weird that there aren't any animal-/truck-towed direct fire or indirect fire pieces on the fields of W40k, at least the way it is represented in the FFG roleplaying games. then it struck me and I had a "duh" moment: all of that shit got miniaturized into lascannons, multi-las, autocannons, heavy bolters, and fairly efficient mortars that can fit many different types of ammunition specialized for a diverse set of situations. you no longer need to do WWII-style tactics with hidden battle cannon emplacements (like how germans used their PaKs, deadliest anti-tank killers on the western front), instead you got all that in a neat sub 40 kilogram package that is way more destructive as well.
still, even with such nifty man-portable weapons, there is a substantial amount of enemies on the war fields of W40k where not even the mighty lascannon can do much more than a scratch (again, referring to FFG roleplaying games, I have no clue about the tabletop). if I recall correctly, even the defiler can take a lot of pounding from a lascannon, and there's no shortage of equivalent machines for most factions you fight in these games. some of them are even tankier than that, and I have a hard time fathoming placing such units in a game as a game master without accidentally wiping out the entire party.
which made me wonder: you would think that there would be more instances of guardsmen drawing battle cannons (maybe even with the help of ogryns lmao) or otherwise using their standard vehicle weapons in unorthodox ways. motorized and mechanized infantry is not always tenable, or even desirable, and instead you would want to opt in for a more guerilla approach with your heavy arsenal. anybody knows of anything like that being represented in W40k? if so, let me know.