When quadguns explode they look the same but on fire. It would be nice if these assets could be swapped for these ones I found on medusa.

Quads respawn so it makes sense for t to be on fire, fire kills things inside and disables quad. Fires goes out quad is able to be used again (respawn). Would be asthethically unappealing for me to see such a destroyed husk just go poof back to normal.

Does it really make sense? Why/how do quadguns magically self repair without player or bot(Tech Priest bots) intervention? It's extremely lame that quadguns self repair. If a quad gets destroyed, it should stay destroyed the duration of the match.

As far as the topic at hand, I totally agree. Why not used the burned out model?

Making use of the standard bs logic of things it makes sense how? The warp that's how, every thing in da game is tainted that's how we keep respawnining on the same map over and over again. Also one can always go with nano bots, if the warp ain't enoufgh . Putting aside the balance aspect and our feelings as the quads respawn it's more logical if burning " destroyed" ones stop burning and "respawn" so that's it's useable again than a totally busted hulk of scrap metal and busted parts "destroyed" suddenly becomes brand new "respawn"

Which would you rather see a stuck metal door on fire stop being on fire and working again or a totally rusted and corroded metal door suddenly loose all its rust and corrosion and look brand new

Actually a more believable and 40K appropriate mechanic would be to see the quad gun lower into the floor of the wall or structure where it is mounted when the gun is knocked out.

That's actually quite common in many 40K novels aboard space going vessels and inside various types of installations. I've read of probably a couple hundred different examples in various 30K and 40K novels about gun servitors and various types of automated or manned turrets that can be "deployed" from compartments hidden inside walls, from floors, from various types of terrain(snow, ice, rocks, etc), or dropping down from a hidden compartment located inside of a ceiling. The weapon platform emerges from it's protected compartment, shoots stuff up, then the weapon can be retracted back into the bulkheads for protection or to allow for rearming or repairs.