Could I suggest that we keep to discussing one unit at a time or set up multiple threads for each units which needs to be discussed? If we don't do this, then posts are going to get overlooked, and we're going to have a rather haphazard discussion where people keep jumping from one topic to the next, which is very difficult to follow, and makes drawing conclusions very difficult.
Following my own advice, I'm just going to talk about Khorne Daemonic Assault Engines.
First, I must declare an interest. Khorne's Daemon Engines have, alongside Tzeentch's Daemon Engines, are my favourite units from the old Chaos army from Space, and are the main reason why I play LatD forces, so I do have strong opinions about them, which I will do my best to moderate in the interests of reaching an agreement.
Second, this is going to be one of the few occasions I suspect where I agree with a number of Lordotmilk's suggestions for change

. There is, however, a line which I think that we're going to have to decide on whether to cross quite early on, and that regards the uniqueness of the Daemon Engines.
All of the Nurgle and Tzeentch Daemon Engines retained their individuality from Space Marine (i.e. separate names and stats), but the six Khorne Daemon Engines lost this, and were just lumped together under one set of rules. I understand why this was done, but it does bother me a little bit, and
ideally (note the emphasis) I would like to see them separated back out into individually named Daemon Engines.
Unfortunately, realism dictates that this isn't really such a good idea, owing to the fact that this would add yet more units/formations to the list, and that's something that most players here don't seem to want, and it's also impractical, because very few players, I suspect, myself included, have three of the same Daemon Engine to put into one formation.
My collection, for example, consists of two of each of the Tower of Skulls, Cauldron of Blood and Death Dealer, and one of each of the Brass Scorpion, Blood Reaper, and Doomblaster.
We could, of course, adopt a mixed formation à la Space Marine, but that would make the formation somewhat difficult to balance in terms of the rules, and could make for quite a bit of role confusion. As a result, I doubt that it's terribly practical.
The simplest fix, in my view, would be to increase their FF to 4+. Daemon Engines are supposed to be fearsome in an assault, and while I have found them to be pretty good in base contact, their FF lets them down in a big way against the sort of infantry formations I would expect them to be able to beat. I certainly would recommend play testing this first before making any more exotic changes.
Another small change which could be made would be to give them thick rear armour. Considering they had a 2+ all around save in Space Marine, and they are meant to be very tough, I don't see why this cannot be added on top of reinforced armour.
Finally, I don't think that they need champion options, icons, or anything like that, and I also doubt that they need a formation size increase. We could experiment with the idea of giving them back their names, and allowing mixed formations, but that would be something to play test after the FF increase.
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Soñando con una playa donde brilla el sol, un arco iris ilumina el cielo, y el mar espejea iridescentemente.