First of all, thank you for the whole work and time that you put in this game and that we as Warhammer fans have a game to enjoy.
Now the idea including explanations:
In my view, the roadmap makes sense and gives us some transparency. However, I personally are not sure whether the decision on balancing is the right one.
As you already emphasized in the "Ability Recwork", it was primarily about simplifying things so that you can improve/adapt it faster afterwards.
In my view, you should also tackle this in the classes and balancing.
There are many classes that are not only similar but actually play completely the same. Of course, some skills are distributed differently, not only on the mirror-classes of the other faction, but also spread over other classes. (let's say heal debuff, wounds buff for grp and many many more)
Therefore, it might be an idea to completely mirrorthese classes and "simplify" them first. Same goes for Sets (Boni) or let's say Fortress Weapons.
If f.e. Dok and WP are completely identical, there is no longer a balance problem here. Of course there are a few differences, but if you compare this, create a list of what has been taken away or added to compensate for it and which buffs/debuffs are overall available on this class now.
As soon as it is completely "Balanced" in terms of mirroring, there is little to complain about. Then you can add special skills and improve the class identity. For example, that a DOK increases the group damage % and a WP reduces the incoming damage %. Just as an example.
Actually, this works entirely for all classes in Ror, since they are not so different at all.
The only exception are Squigherder VS Shadowwarrior and Marauder VS White Lion. I would only tackle and adapt these four classes at the end. Since everything else is mirrored and more or less balanced (mostly mirrored by then). That means only 4 variables would be left for complete balance.
Then you have a good starting point in order to be able to make further changes and to be able to value the class identity more.
(Example KOTS/Chosen Auras > give them good icons/names but make them do the same. Just give let's say -x% inc healing and (enemy) + x% healing done (friends) to both classes as an aura. Boom, balanced. You can add fancy class identity stuff later <3 )
I don't really see any other way for a balance team to get things done right as you have to keep in mind soooo many minor stuff and everything is a chaotic mix right now, which will most likely make it impossible to really balance it anyway. But best of luck

In this context, since many players are always happy when they see a complete group consisting of Greenskins or Dark Elves (ofc also on order races), one could even give such groups a buff, as soon as this baseline for balancing has been created.
That would mix up the meta setups a bit and will make, let's say, two blackguards and two Doks more useful in the same party.
Like Adding A Buff With Having 4-6 Members of the Same Race in A Grp.
"For the Witch King-> Increases All Your Stats BY 5%-7%-10% depending on the number of Dark Elves in Grp.
These numbers and bonuses are just an idea and serve for better description/visualization. Which bonuses are possible is of course among the Developers and the Balance Team to decide.
However, it would promote more group diversity (meta setup wise) and also support the RP aspect of the game.
So now you can burn me for these ideas and shame me <3
(I believe in our RoR Team and hope for the best, it's just that I have wished it would go into that direction first (> see above) and that instead of having the big monster of a project, a kinda simplified baseline first.)
EDIT: Forgot to add:
The idea of also looking at small scale or even 1on1 or roaming, balance wise, is nice yes ... but you should only focus on one thing right now and not make it more chaotic as it is. Therefore, please balance around warbands or 6man grps first as a priority.
These are only suggestions and ideas and ofc by no means negative/critizizing or whatever. You should = I would do this (nothing more , nothing less). Context wise.