That's exactly my point. Total War has its own features, its own mechanics. Code-wise, it is very different from Age of Empires and other RTS. You are giving the example of BFME2, which is both very different from Total War and very different from 0 A.D. in its mechanics.  Implementing charging bonus, morale, fatigue, ammo etc. do not require battle formations. It is actually the battle formations which require new features to make sense. All the mechanics in battle should make sense with the formations. It requires a holistic approach. The challenge is to produce a well rounded design and balanced mechanics based on battle formations. While keeping the other features and design of 0 A.D., notably on the economy.  And also making all that with the current engine, notably the pathfinding. This is a major overhaul. Total War and BFME2 were designed with this idea from the start, don't underestimate the ramifications. It would be great but I don't see how it is feasible with the current ressources and management.

That's a good description of when the message appears but I agree that using the word rejoin in a situation when the user joins the game for their first time is misleading. The game used to be translated using Transifex, but when I last tried to make an account there it was quite a pain.

0 A.D. is changing stereotypes!

Okay. Battalions seem like they could be a good idea, as long as they are OPTIONAL. Replacing individual unit training with battalions is not a good idea, but being able to turn a formation into a battalion (or a group of units into a battalion) seems like it would grant a lot of new features, while being unique.

Okay, so what is the Total War vibe, then? Why does Total War use battalions? Why not just have hundreds or thousands of little dudes running around individually? It's because battalions give the opportunity for greater control for the player, including directional attacks, flanking, charging bonuses, fatigue*, morale*, formation bonuses (and weaknesses)... all of the things that make ancient warfare interesting. You can have the benefit of 1000 soldiers vs. 1000 soldiers battles, but with easier player control and combat dynamics. You'd have a couple dozen entities (battalions) to manage in that example instead of 1000. For all those people who desperately want an 'ammo' feature*, battalions make it easier to do.  And it would be less like Total War and more like Battle for Middle Earth 2:   *Fatigue, Morale, Ammo aren't 100% necessary, just easier to implement and manage if desired.