Barricade building mechanic similar to Battlefield 1, Engineer only.
Engineers would have the option to bring a hammer or wrench, allowing players to build sandbags, ladders, anti-tank hedgehogs and other blockades, with 2 ways of doing it mechanic-wise.
1) Battlefield 1 style, where emplacements depend fully on the map with pre-determined emplacements. Takes extra time, but makes sure that any glitches can be streamlined.
2) free placement. Offer the ability to switch between each emplacement, and allow placement anywhere (within reason, such as ladders near walls, etc). Offer a limited amount so nothing breaks, such as dozens of ladders or sandbags to the heavens (which may happen anyway)
It could potentially be either an alternative option for the repair tool, or a potential class perk (unknown, since I obviously dont know how those will work out)