Ever wondered why your Spanish Jinetes have no shields?

[Xantan]

So in this case, the architecture of the game is bugged, because this is not supposed to happen at all. In the end, it's still a problem of the game.

If only MTW would have been fixed on diplomacy, some more minor bugs fixes + adding some more units (Eastern factions are lacking) and then we would have an impeccably epic game.

Still is epic regardless.

[Gilrandir]

So in this case, the architecture of the game is bugged, because this is not supposed to happen at all. In the end, it's still a problem of the game.

Are you well-versed in the initial design of the game and its real-life implementation that you can claim what was meant to be and what was not supposed to happen?

If only MTW would have been fixed on diplomacy, some more minor bugs fixes + adding some more units (Eastern factions are lacking) and then we would have an impeccably epic game.

If all factions had identical roster there would be no point in choosing them. Different rosters let you try different battle tactics and mirror (with some degree of approximation) the peculiarities of army composition of various real-life medieval polities.

[Xantan]

If all factions had identical roster there would be no point in choosing them. Different rosters let you try different battle tactics and mirror (with some degree of approximation) the peculiarities of army composition of various real-life medieval polities.

S2TW had almost identical rosters and yet it was a very fun game.

It's about the diplomacy mechanics which honestly, in my view, are not ideal. They don't work fully and even by comparison with M2TW we can see that. And also M2TW had problems - I remember trying to play on Very Hard was rather uninspiring since you had to fight sieges every other turn if you played as HRE for example.

[Ludens]

There isn't really much diplomacy in the Total War games anyway(you just attack the weak ones) but i guess changing it would make for a different game. Do you want AIs to stop joining up on you, or maybe have more realistic/historical alliance blocks?
The devs were probably like "we should add a diplomacy screen so that players can spend a bit more time on the strategy part" but that's all, it's not main focus. Maybe even call it cosmetic :)

That's likely true for the first 2 games, though I wouldn't call it cosmetic. Certainly in M:TW, with its crusades and naval trade, diplomacy mattered.

And sometimes the diplomacy was just stupid. The pointless naval wars in M:TW, for example. And in R:TW the A.I. was blatantly programmed to gang up on the player. If you declared war on a faction that was being attacking on multiple sides, its opponents often would make peace instantly. That's pretty immersion-breaking: you think you are making a smart strategic move, but then the A.I. uses a cheatcode.

[Ludens]

I didn't like it at first too but that's probably needed to keep the game fun and for the player to have always a challenge. There is an example from reality too, how Russia made peace with the Ottomans right before Napoleon's invasion.

Yes: before, not during. And frankly that was Napoleon's fault for neglecting to make diplomatic overtures to the Ottomans. He complacently assumed that Russia's neighbours would side with him, and would blunder even worse with the Swedes.

You are right that this prevents the A.I. from being a pushover, but when it is this blatant it feels like cheating. That can be fun or frustrating, depend on what you expect from the game.