But back to world class genius misunderstood during his lifetime, would you think mods will actually start playing a larger part in balance discussions, now that the stuff is official and more established I'd think a few players can take a look and assess just how good the solutions might be. (We'd still need to admit that fans often come up with more conservative half-way solutions than the original developers.)
I think there are basically two types of people who play these games, the sandboxers who play the theme and the exploiters who play the mechanics. This is the source of all the realism vs gameplay arguments. With the new mod system, particularly that mod usage is visible in lobby, mod discoverability is going to be a lot higher. I would therefore expect that there's going to be a lot less arguing about balance overall. All the sandboxers are going to congeal around one or two of the numerous realism mods that are going to be popping up and left to argue about the balance of the base game are going to be those who play ranked. These people, while certainly caring for authenticity to some extent, are primarily going to argue about imbalances, not about things that are wrong in regards to the theme.
Mods are a potent tool in showing how changes can make a thematic difference but they're not very good at resolving balance issues. The reason for this is that you can only percieve a balance state with hundreds of combined hours played in it. Compared to that effort, creating a mod is only marginally more productive than just theorizing about it. So, to answer your question, I don't think there's going to be a lot of balance suggestion mods.
I created my mod because I thought infantry lost fights wrong, they died instead of running away leading to pretty insane casualty rates compared to any real formation (the casualties we have in game would make the first wave at Omaha look like, well, a walk on the beach). I don't have any real complaints about balance at all (well, some), but I do think that some things should work differently for a better experience.