I have read only the first few posts, so sorry if the discussion has developed further. All I will do is posting my personal opinion on that matter and on your OP.
1. Cavalry and archers are not OP. There are only too many of them, making them look like OP. In fact they are UP.
2. There are two reasons why nerfing is not a good solution. Reason 1 is that the game is already nerfed down to hell. Reason 2 is, that although those classes are nerfed to the ground, they are still popular. So another nerf won't help it.
3. I know you don't believe in the solution, but changing the game mode from battle to conquest would perhaps not instantly fix all issues, but sure as hell it would improve things a lot. And I don't think it's that unlikely they will implement it (given they WANT), they already have implemented a lot of fantastic stuff.
4. There are also a few other ideas which would help the whole matter, for example implementing a well working commander feature (admittedy this IS very unlikely
), or buffing infantry instead of nerfing the other classes. For example an armour buff is pretty much welcomed by the majority of the community
5. A nice side effect of the conquest mode would be, that some UP classes like cavalry and archers could get buffed again
The problem we are facing has a lot of different reasons, be it the average skill level of the community, medieval warfare never meant to be fair (thus making it difficult to implement in a fair game, e.g. a working rock-paper-scissors-system), the higher need of infantry to play in a team or the weird effect that the effectivity of cavalry and archers raises the more there is of them, without the need of actually playing together, and finally the already mentioned problem of the game mode asking a goal ("kill all enemies") of classes which don't really have the tools for it (infantry vs. kiting ranged). Even the upkeep system is a part of the problem, as it doesn't really fullfill its purpose as equipment limitation and thus forced the developers to keep the viability of different items on different levels to encourage/duscourage the use of certain items. There is no way lowering some stats could help those problems.
I am honestly disappointed of what I heard of the new patch, because just nerfing DGS/GGS, Rus Bow, Heavy Lance and other popular items and buffing a few alternatives, or buffing archer armour to make them slower spposedly, is a solution which is to compare with sawing off the too long legs of a chair to prevent it of wobbling, just to create another pair of too long legs, until the chair has no legs left. It lacks imagination and basic understanding of the problem. A few of those changes were reasonable, but at the moment we have different problems, like Thomek noticed very well.