That video isn’t REALLY about just trebs when you try to analyze it as somebody that was following this game, and most likely playing recently, for a while.
Every single element mentioned in that vid element represents the uncertainty and fears about the general state of the game. Trebs are a placeholder, an example to use, without breaking NDA, to maybe talk about it.
It’s not like every unit, building etc has its own set of 3d artists, animators or sound designers assigned to work on it. When you have some doubts and worries about the sound effects of treb projectiles - that can potentially cover and extend to a much wider array of in-game elements.
Mentioned animations of treb, visibility of the projectile, trails it leaves on the screen and impact it causes can refer to torches, arrows, cannon shots and many others.
The way buildings are affected by its fire can be stretched to other siege units.
Destruction mechanics is the same whether a building is destroyed by a treb, shock infantry, cannons or anything else.
And it has nothing to do with style of the game, visuals tones. It’s not out of the line to expect from AAA full priced game to have good basic mechanics involved throughout the entire game, in every single game, in a way that doesn’t only impress today but has potential to stand the test of time for at least couple of years Think of physics in Half-Life 2, AI in F.E.A.R.
I can have the most stylized soldiers AoE have ever seen, but I still want to see them equipped with sufficient number of well-made animations that make sense and properly represent my input and their actions on the field. With well-designed sound, properly adjusted models and meshes that doesn’t leave an impression of cheapness, incompetence and indie-ness (with all respect to Indie devs out there!).
This game is primarily about warfare and every single element that contributes to that gameplay loop should be as good as it can be - you can spend a mountain of money to create a beautiful game with an amazing story, but if controlling units, destruction, gore, UI etc. doesn’t feel good- playerbase will start to bleed very quickly.
Nobody is really presenting any demands about building, gathering resources etc. because these are secondary elements.
Please remember AoN said few times he got more positive to say about IV, but can’t because of NDA
And just like with most of complaining in places like that - most of the time it’s not a reflection of terrible state of the game, just very high expectations and passion for the project.