Vertical warfare, promotion of camping, and bad map design choices
Hourglass, Discarded, Kaleidoscope, and especially Manifest all have objective with little to no cover, and tall infrastructures that just promote camping and sniping as the only viable play styles in this game.
Manifest in particular, the large cranes (or whatever they are called) that overlook objectives C1 D1 promote camping, and with objectives C1 D1 having barely any overhead cover, it makes taking those objective very difficult unless the players on the cranes are your own teammates. On this map, being a sniper or using vehicle seems like the most viable way to play, which is an issue on Breakthrough mode, with too many vehicles, and access to those cranes on C1 D1.
Discarded, objective B1 - I'd like to know which developer thought it was a good design choice to put that tall tower literally right over the obective B1, which itself has literally zero cover. Once again, being a sniper or a vehicle user seems like the only viable way to play this objective.
Hourglass - I think that speaks for itself. Too many vehicles. Remove air vehicles at the very least for that map, and provide a lot more cover across the dessert area.
Kaleidoscope - Below is an image of the concept art for one of the areas of the map, as you can see, lots of cover, debris, broken infrastructure, and bad weather and visibility that would make camping and sniping very difficult. But the launch edition of the map look nothing like it, with zero sign of warfare, little cover, and tall infrastructures that that are occupied by snipers, which in turn lessens infantry gameplay back on the ground.