To win a game you have to win your opponent who have same opportunities as you do. Where is part in that what makes it easy?
Well first this game isn´t just about defeating your enemy. I for myself play this game because i have fun at building my town and then there is also the nice part of fighting after pt. If i lose or not is not important as long as i had fun at building and had some nice fights. So for me the game isn´t fun anymore when the buildingpart gets too easy ( like infinite wood , no worries about food , big army without problems ) because there is no challenge in building and building is like 60 minutes of around 90 minutes of the whole gametime so quite a big part

. You ever cheated in a game like give you infinite money in Sims or something comparable ? It might be funny in the first minutes but soon it gets boring because you can´t archieve something special anymore.
Easy vs easy is same as hard vs hard.
Ok another example : You have some students in school playing basketball against each other and two top teams in the NBA playing against each other . Its like in both cases both teams have the same opportunities to win , so it must be the same right?

Nah really if you would compare those games you would see a clear difference espeacially regarding the competence and the need for skills. Those NBA team players will keep playing basketball because everyday they get an other challenge and like that keep their interests in the game. In school one or two sportlessons of basketball might be nice but then you´ll get sick of it because it won´t give you big challenges , so you ask your teachers to play something else in the next lessons to get a new game with some new challenges.
And the same applies to KaM . In easy games you can do everything you want and you´ll be fine. You won´t have any challenges so the game will get boring. In hard games you will always get new challenges . For example every game there can be new gaps in your town which could mess up your town and you need to fix them. Like that you can never say what awaits you in the next game because the building gives new traps and people might mess up or can play very good . Thats why i play golden cliffs very often and never get sick of it because its a hard map and it is different every single game. Even today i can say that there are still some locs on golden , which are quite challenging for me and even on the locs that i know very good i might still step into some traps. This hard map keeps challenging me and like that the building is really much fun for me and the time after pt is even more interesting because you never know how your enemy performed.
In easy games only a really few things are challenging and you know that everyone will have a good army after pt so there aren´t any surprises.
So really : easy vs easy and hard vs hard are
not the same
Can any one explain to me why is bad to have large army or good city?
Ohhhhh, i have the perfect example for you

. Ever played Border Rivers? That map is the best map to explain that big armys are not good after pt. That map has just no space for big armys. It´s like whoever will attack will take big losses because the enemy big army is waiting at their entrance and can just shoot at you while the frontline is fighting at 10-15 tiles or so . And all the rest of your army is piling behind that frontline, just waiting to get killed by the defender . Now you maybe say " Hey but with more army you can make more manouvers because you have more troops to use! ". Well first there has to be space for manouvers. Without space its just a big pileup-fight like on border rivers. And second how you want to flank succesfully if the enemy just has like 50 troops left to defend against your flank. Also flanking is most usefull in the moment where you can surprise your enemy with that flanking . Now try to flank with a dangerous amount of units ( If everyone has like 100+ units it have to be like 20 or so to be a kind of a threat ) without being detected. It will be just always a big fight where 2 armys just charge eachother without any chances of flanking. So again there is no challenge in fighting because you can´t really do much to improove your attack.
With smaller armys there are much more possibilities and things you have to watch for. Even small things can really get to your disadvantage . One knight flanking you can be really gg sometimes because you dont have enough soldiers to protect your rangeunits or you didn´t pay enough attention. Now if you caught this knight after he killed some units it might be ok with the large armys but with the small armys it can be very devastating for you because every unit counts. Also flanking with 10 militia can be very good because the other guy has to send meleeunits to protect that flank against the militia while he normally badly needs those troops to hold the frontline.
There won´t be big pileups with troops and like that every unit counts, every decision has to be made wisely and mistakes can mess the fight much more up as they could in fights with large armys.
So again here is the challange which makes playing with small armys much more interesting.
And regarding the way you got the large army or good city is also very important.
It´s exampletime again

: You want to bake a pizza. Now you´ve got 2 options : You get a recipe and gather all the ingredients and make the pizza yourself or you just go buy a frozen pizza from the supermarket and put it into the oven.
The selfmade pizza was quite a hard job and demanded some skills from you . But somehow the pizza was just ok. The frozen Pizza needed no skills ( maybe using the oven

) and was also ok but maybe also better than the selfmade one.
So now the question : What are you prouder of ? The frozen pizza or the selfmade one ? And which one made more fun to do ?
The answer is quite obvious . Ofcourse you are prouder of the selfmade one even though it wasn´t as good but it was fun to make the pizza. The frozen pizza was just easy and didn´t demand anything from you. You hadn´t any fun at making it ( maybe you watched a funny clip on youtube while you were waiting but that doesn´t count

) .
This example might be a bit extreme but it fits. You can make big armys but if you had no challenge at making them where was the fun there? Better have a smaller army while having a challenge making it ( making a large army with big challenge is even more fun ) . So this is why big armys and big citys are bad when you have no challenge building them and with the easy unbalanced maps at the moment there won´t be that challenge.