Dont think they would.
At least not if both alliances have spent approximately the same amount of recourses.
Dont see them defending 100 locations successfully if they wont even know which locations will be hit.
Maybe give it a thought and let it sink in. The situation is when you have used the same amount of resources, which approach is more "effective". Full Attack or 2/3 Attack and 1/3 Defense in this game.
More attack troops let you also farm more.
They would also take devastating damage for sure on many cities even if they would have gained approximately 10-30% more resources in the game and have more members.
Also, i would guess any alliance would rather have a war with 2/3 attack 1/3 defense + scout alliance than 3/3 attack one of similar size.
If you think about "catching the armies" you can do it with your Axemen if you want, which have low defense against attacking Axemen, which have high attack. As at least 2/3 of your troops are attacking troops too, but ours are attacking, and yours try to intercept our attack. If you attack with 2/3 you are attacing with less than us, and defending 3/3 with 1/3. Its clear to me which side gets worse damage, and is more crippled after one exchange. For example, the 2/3 attack alliance will almost certainly lose 1/3 of their troops and the 3/3 attacking alliance wont. So after the exchange, they have more troops for another go. I think im pretty sure that Offense wins against Defense in this game.
So there are some reasonigns behind my suggestions earlier. Simple Minded Annihilation is what i would call that strategy, full offensive.
Its not clear to me yet, can you or can you not see the attacking army sizes. If you would see the army sizes, then making "defensive armies" would be adviceable again. The whole purpose of not making them is the thing called "Fake Attack". It is a strong advantage for the aggressor against the defender. Especially if it is a game mechanic which cannot be affected. All i wrote above is applied only if you can use the "Fake Attack" approach. If you cannot, defensive troops would be viable.
Not saying i plan to do any of that, just saying what i think would be effective in a given situation. How to use your resources in the most effective way. The full purpose was trying to explain why i dont like the "Fake Attack" as would seem it is and tried to give suggestions for people to go around it. But probably its a major no go, as the gold buying player base would be furious if anything is done to that feature in the game. So nothing more about that. Still, there might have been some ideas that could lead to something actually viable in the game. There have been some ideas from other people that i think are good too, so the developers are doing the right thing when asking from the players what they do or do not want.
I also noticed Travian Legends special server standings, the top players were Huns. Huns gain access to fast and strong offensive units, but lack almost any good defensive units. Of course they win the server by large margin, as they specialize in strong and fast attacking troops + raiding and their "balancing weakness" is defense. It enables just the type of gameplay i described, to go even full offensive if needed.
One thing to do is, to make the spotting a bit random, so the code would check a spotting roll that is affected by number of scouts or other modifiers and their upgrades, and the estimate is not always accurate, so the player might get wrong information too. So you cannot always trust what your intelligence services are telling you but they can give you estimate. Of course one troop approaching is very hard to mistake for a 100 000 strong invasion army and vice verca. But it might be hard to know sometimes, is a large force around 10k or 100k with a glance, or without closer inspection. Also, the report could change and there could be checks when they are closer, so even the spotting distance could be divided into short, medium or long distance. But these type of approaches are probably too complex for this type of game.
The entire "Fake Attack" feature is viable in a fantasy setting where they use Illusions or Sci Fi setting where they use Holograms. Then you really might not know. My one suggestion was to include Magic or Mysticism to Travian in some way. For example Hero skills, Perks or so. A Mage Hero could do just this, shroud the approaching army that it cannot be seen, or use an illusion to mask it as a larger or smaller force. This again, sounds more lika Travian 2 than a new feature in the game.
So, my final suggestion is not only continue to Improve Travian, but to plan for Travian 2 too.