The latest expansion pack has been released. Now, certain things are clear.

Fix and add, but don't change. An add-on with completely reworked units of all factions will not be one. It will be a new part.

Firstly, add-ons include modifiers, so they change things, among other things. Secondly, after the last add-on, due to the number of additions and changes, some consider the resulting product to be HoMM 5.5 (you can read about it on official websites) – isn't that another part? Thirdly, adding a new faction and alternative units is a contribution that can change the degree of the trend (precisely the degree), even though it "fully complies with the graphical style of the base."

…and in my opinion, to talk about such a trend, you need to at least look at the 3D third game in comparison with the fifth, or at the sprite-based fifth in comparison with the third. Since this is impossible for obvious reasons, the only option is the future 3D HoMM6.

Firstly, for obvious reasons, this is possible. And even easily. Secondly, there is no difference in the differences in the principle of constructing graphics. You can discuss the cartoonishness in 2D, 3D, 4D, or… And you can discuss the trend (directed) when there is a group of interconnected elements located sequentially on a time interval, no matter how different they are (the main thing is that they claim to be part of one series). Do we have this? – we do! It's a different matter here:

Well, I don't see the trend you're talking about. Even if it's like this - I can't make out this trend. It doesn't seem to me that the units in HoMM 5 are more cartoonish than the units in HoMM 3.

You don't see it – I understand, there are no problems with this, because everyone sees things differently. I believe that the degree of cartoonishness has increased, you – don't. Olga gave you several examples, you either agree with them or not. But to say that it is impossible to observe a trend at all – you are wrong.
We can argue about whether "The Hedgehog in the Fog" is the best cartoon of all time or not. I agree with this statement more than not, but there are people who claim that this cartoon is absolutely absurd, and not only does it not claim to be something high and bright, but it is generally complete nonsense and should not be shown to children (even to that extent). Everyone is different, and everyone has different views.

I think that you and I will agree that HoMM V is a great game. We still won't argue about anything, in the sense that we won't convince each other. I shake your hand as a good opponent; after all, we didn't descend to personal attacks. You are right, and I am right, and that's it.

If Nival and Ubisoft want to end the game like this, without the Swamp faction, they are wrong.

Yes, it's a good faction. It's a pity that it has already been slightly incorporated into the 5th game.