They are the attached transports for our assault/cqc/melee forces.
Said forces are also for the most part be equipped with weapons that are focused on short range so open-top designs make not nearly as much sense for them.
To be honest, I can see a strong role for them for line infantry as well. There will be plenty of scenarios where you want them to disembark where an enemy might be able to spot them, and having more armour makes the transport more likely to survive an artillery barrage air bursting over your head.
If RL can be any guide to Warhammer, which it may not be, artillery is the major cause of casualties so something that we need to particularly focus on defending against, particularly as holo-fields are particularly weak to it.
i don't see the problem at our tech level.
1) Use a holo field to become completely invisible
2) Mount some specialized shields to make those anti infantry weapons bounce off
3) Support your assault squad with vehicle mounted weapons. hell, just toss a bunch of screamer grenades.
That should buy enough time for disciplined assault troops to engage.
Moving around or under a grav vehicle is a worse choice, because you'll get shot even more.
The problem is that none of this stops an artillery shell catching you while the transport is briefly stationary for troops to disembark.
Holofields aren't cloaking devices. They're described as working like this
Rather than a typical force field which directly blocks an attack a holo-field distorts the user's image, preventing them from being hit in the first place. When stationary the field mimics the surrounding terrain so that the person or vehicle becomes invisible, but when they move the field causes their image to explode into a cloud of tiny, multi-coloured fragments, with the fragments dispersing more widely the faster they move and then collapsing back together as the subject stops, giving rise to the term jigsaw or domino field.
A holo-field spoofs your location while you're moving, then, when you stop moving, your location is briefly revealed as the image collapses back together before you fade into the background. Basically, holofields don't update fast enough to be invisible while moving, from this description.
This means that transports are particularly vulnerable. Unlike other grav tanks they can't keep perpetually moving so that aimed fire against them doesn't work. To do their job they have to stop to drop off and pick up infantry. This seems to make them momentarily visible for something to focus fire on them before the Holo-field matches the background.
Enemies know that a moving Holo-field equipped vehicles are there and roughly where they're heading, as they can see the cloud of multi-coloured static moving around. They just don't know where in the cloud the vehicle is. They can just saturate the cloud with artillery though, which is why that works as an anti-holo-field tactic, or wait for the vehicle to stop moving and track where it stops, as even if it then turns invisible if you keep watching you know that it'll be where it vanished.
And this isn't just for assault troops. Any infantry deploying from a transport is bunched up and vulnerable to artillery or long range fire, not just specialist melee units.
The only power who aren't vulnerable are troops operating out of weapons range of the battlefield, and they can use grav barges and don't need a militarised vehicle.
Yes but if you're assaulting from a vehicle, you can't do that while the vehicle is in front of you. you're going to be exposed regardless.
That's why you assault around the sides of the vehicle using it as cover from enfilading fire.
