No, that makes no sense at all. That is exactly the thing i am arguing against. If we have small squad actions, i want there to be a Plausible, In-Game reason. Not an arbitrary reason.
Think of a map 100 x 100 hexes, only the Chasm's are only 3 hex's wide, and there are strange restrictions like only 3 units per tile or something ... Or to go SUPER crazy, only one person per tile
This is Exactly what i mean. Why is it only 100 x 100? why only a certain number of units per tile? All completely arbitrary reasons. All break the immersion of the game. I might have a vast army with me, but they can't enter the fight because the map is only 100 x 100? That is flat out arbitrary.
You just don't like questing, I feel like, and I don't think your revilement of a feature should be enough for it to be removed.
I love questing. Of the quests that frogboy posted in his op at this thread https://forums.elementalgame.com/372222 every single one has a reasonable requirement that is explained in game. However, you will notice, that only the incidental quest restricts the total number of forces you can use. Which makes sense. It is a small inn, and you are only killing rats. That is a good reason to only involve your hero.
The other 2 examples are taking a castle and fighting a demon. In both of those cases, the only restriction is that you need a hero with you, which makes perfect sense. If you want to bring your whole army along, all well and good. I don't plan on fighting a demon or seizing a castle with just my hero.
Maybe your huge squad of Zombies is possible through a combination of Military Techs + Necromancy Spell book, or maybe all it takes is alot of Mass-raise-dead spells from the Necro spell book. And if its not there? and even if it is? There will probably be an economic and time-based things. What you propose ... about taking zombies to tear the place down brick by brick ... I would say would require at least 1000 zombies in the area to maximize the speed at which you would slowly be dismantling the Dungeon.
The zombies are just an example. Any unit you can make lots of could work there. Instead of zombies you could use any cannon fodder unit. Peasants with sticks, spearmen, basic infantry, anything. I just say zombies all the time because they are by far the coolest cannon fodder unit. It dosen't even have to be a cannon fodder unit. Any large army would work.
Ok, since my postion is still not obvious, let me clarify.
I love small squad combat. I love small squad combat. I LOVE SMALL SQUAD COMBAT. 
I just want there to be a good reason for why i can't bring in my massive army. Thats all i ask for. That is all i want.